Adding upstream version 86.0.1.upstream/86.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

12 files changed, 3748 insertions, 0 deletions

diff --git a/third_party/python/six/CHANGES b/third_party/python/six/CHANGES
new file mode 100644
index 0000000000..ffa702601b
--- /dev/null
+++ b/third_party/python/six/CHANGES
@@ -0,0 +1,315 @@
+Changelog for six
+=================
+
+This file lists the changes in each six version.
+
+1.13.0
+------
+
+- Issue #298, pull request #299: Add `six.moves.dbm_ndbm`.
+
+- Issue #155: Add `six.moves.collections_abc`, which aliases the `collections`
+  module on Python 2-3.2 and the `collections.abc` on Python 3.3 and greater.
+
+- Pull request #304: Re-add distutils fallback in `setup.py`.
+
+- Pull request #305: On Python 3.7, `with_metaclass` supports classes using PEP
+  560 features.
+
+1.12.0
+------
+
+- Issue #259, pull request #260: `six.add_metaclass` now preserves
+  `__qualname__` from the original class.
+
+- Pull request #204: Add `six.ensure_binary`, `six.ensure_text`, and
+  `six.ensure_str`.
+
+1.11.0
+------
+
+- Pull request #178: `with_metaclass` now properly proxies `__prepare__` to the
+  underlying metaclass.
+
+- Pull request #191: Allow `with_metaclass` to work with metaclasses implemented
+  in C.
+
+- Pull request #203: Add parse_http_list and parse_keqv_list to moved
+  urllib.request.
+
+- Pull request #172 and issue #171: Add unquote_to_bytes to moved urllib.parse.
+
+- Pull request #167: Add `six.moves.getoutput`.
+
+- Pull request #80: Add `six.moves.urllib_parse.splitvalue`.
+
+- Pull request #75: Add `six.moves.email_mime_image`.
+
+- Pull request #72: Avoid creating reference cycles through tracebacks in
+  `reraise`.
+
+1.10.0
+------
+
+- Issue #122: Improve the performance of `six.int2byte` on Python 3.
+
+- Pull request #55 and issue #99: Don't add the `winreg` module to `six.moves`
+  on non-Windows platforms.
+
+- Pull request #60 and issue #108: Add `six.moves.getcwd` and
+  `six.moves.getcwdu`.
+
+- Pull request #64: Add `create_unbound_method` to create unbound methods.
+
+1.9.0
+-----
+
+- Issue #106: Support the `flush` parameter to `six.print_`.
+
+- Pull request #48 and issue #15: Add the `python_2_unicode_compatible`
+  decorator.
+
+- Pull request #57 and issue #50: Add several compatibility methods for unittest
+  assertions that were renamed between Python 2 and 3.
+
+- Issue #105 and pull request #58: Ensure `six.wraps` respects the *updated* and
+  *assigned* arguments.
+
+- Issue #102: Add `raise_from` to abstract out Python 3's raise from syntax.
+
+- Issue #97: Optimize `six.iterbytes` on Python 2.
+
+- Issue #98: Fix `six.moves` race condition in multi-threaded code.
+
+- Pull request #51: Add `six.view(keys|values|itmes)`, which provide dictionary
+  views on Python 2.7+.
+
+- Issue #112: `six.moves.reload_module` now uses the importlib module on
+  Python 3.4+.
+
+1.8.0
+-----
+
+- Issue #90: Add `six.moves.shlex_quote`.
+
+- Issue #59: Add `six.moves.intern`.
+
+- Add `six.urllib.parse.uses_(fragment|netloc|params|query|relative)`.
+
+- Issue #88: Fix add_metaclass when the class has `__slots__` containing
+  `__weakref__` or `__dict__`.
+
+- Issue #89: Make six use absolute imports.
+
+- Issue #85: Always accept *updated* and *assigned* arguments for `wraps()`.
+
+- Issue #86: In `reraise()`, instantiate the exception if the second argument is
+  `None`.
+
+- Pull request #45: Add `six.moves.email_mime_nonmultipart`.
+
+- Issue #81: Add `six.urllib.request.splittag` mapping.
+
+- Issue #80: Add `six.urllib.request.splituser` mapping.
+
+1.7.3
+-----
+
+- Issue #77: Fix import six on Python 3.4 with a custom loader.
+
+- Issue #74: `six.moves.xmlrpc_server` should map to `SimpleXMLRPCServer` on Python
+  2 as documented not `xmlrpclib`.
+
+1.7.2
+-----
+
+- Issue #72: Fix installing on Python 2.
+
+1.7.1
+-----
+
+- Issue #71: Make the six.moves meta path importer handle reloading of the six
+  module gracefully.
+
+1.7.0
+-----
+
+- Pull request #30: Implement six.moves with a PEP 302 meta path hook.
+
+- Pull request #32: Add six.wraps, which is like functools.wraps but always sets
+  the __wrapped__ attribute.
+
+- Pull request #35: Improve add_metaclass, so that it doesn't end up inserting
+  another class into the hierarchy.
+
+- Pull request #34: Add import mappings for dummy_thread.
+
+- Pull request #33: Add import mappings for UserDict and UserList.
+
+- Pull request #31: Select the implementations of dictionary iterator routines
+  at import time for a 20% speed boost.
+
+1.6.1
+-----
+
+- Raise an AttributeError for six.moves.X when X is a module not available in
+  the current interpreter.
+
+1.6.0
+-----
+
+- Raise an AttributeError for every attribute of unimportable modules.
+
+- Issue #56: Make the fake modules six.moves puts into sys.modules appear not to
+  have a __path__ unless they are loaded.
+
+- Pull request #28: Add support for SplitResult.
+
+- Issue #55: Add move mapping for xmlrpc.server.
+
+- Pull request #29: Add move for urllib.parse.splitquery.
+
+1.5.2
+-----
+
+- Issue #53: Make the fake modules six.moves puts into sys.modules appear not to
+  have a __name__ unless they are loaded.
+
+1.5.1
+-----
+
+- Issue #51: Hack around the Django autoreloader after recent six.moves changes.
+
+1.5.0
+-----
+
+- Removed support for Python 2.4. This is because py.test no longer supports
+  2.4.
+
+- Fix various import problems including issues #19 and #41. six.moves modules
+  are now lazy wrappers over the underlying modules instead of the actual
+  modules themselves.
+
+- Issue #49: Add six.moves mapping for tkinter.ttk.
+
+- Pull request #24: Add __dir__ special method to six.moves modules.
+
+- Issue #47: Fix add_metaclass on classes with a string for the __slots__
+  variable.
+
+- Issue #44: Fix interpretation of backslashes on Python 2 in the u() function.
+
+- Pull request #21: Add import mapping for urllib's proxy_bypass function.
+
+- Issue #43: Add import mapping for the Python 2 xmlrpclib module.
+
+- Issue #39: Add import mapping for the Python 2 thread module.
+
+- Issue #40: Add import mapping for the Python 2 gdbm module.
+
+- Issue #35: On Python versions less than 2.7, print_ now encodes unicode
+  strings when outputing to standard streams. (Python 2.7 handles this
+  automatically.)
+
+1.4.1
+-----
+
+- Issue #32: urllib module wrappings don't work when six is not a toplevel file.
+
+1.4.0
+-----
+
+- Issue #31: Add six.moves mapping for UserString.
+
+- Pull request #12: Add six.add_metaclass, a decorator for adding a metaclass to
+  a class.
+
+- Add six.moves.zip_longest and six.moves.filterfalse, which correspond
+  respectively to itertools.izip_longest and itertools.ifilterfalse on Python 2
+  and itertools.zip_longest and itertools.filterfalse on Python 3.
+
+- Issue #25: Add the unichr function, which returns a string for a Unicode
+  codepoint.
+
+- Issue #26: Add byte2int function, which complements int2byte.
+
+- Add a PY2 constant with obvious semantics.
+
+- Add helpers for indexing and iterating over bytes: iterbytes and indexbytes.
+
+- Add create_bound_method() wrapper.
+
+- Issue #23: Allow multiple base classes to be passed to with_metaclass.
+
+- Issue #24: Add six.moves.range alias. This exactly the same as the current
+  xrange alias.
+
+- Pull request #5: Create six.moves.urllib, which contains abstractions for a
+  bunch of things which are in urllib in Python 3 and spread out across urllib,
+  urllib2, and urlparse in Python 2.
+
+1.3.0
+-----
+
+- Issue #21: Add methods to access the closure and globals of a function.
+
+- In six.iter(items/keys/values/lists), passed keyword arguments through to the
+  underlying method.
+
+- Add six.iterlists().
+
+- Issue #20: Fix tests if tkinter is not available.
+
+- Issue #17: Define callable to be builtin callable when it is available again
+  in Python 3.2+.
+
+- Issue #16: Rename Python 2 exec_'s arguments, so casually calling exec_ with
+  keyword arguments will raise.
+
+- Issue #14: Put the six.moves package in sys.modules based on the name six is
+  imported under.
+
+- Fix Jython detection.
+
+- Pull request #4: Add email_mime_multipart, email_mime_text, and
+  email_mime_base to six.moves.
+
+1.2.0
+-----
+
+- Issue #13: Make iterkeys/itervalues/iteritems return iterators on Python 3
+  instead of iterables.
+
+- Issue #11: Fix maxsize support on Jython.
+
+- Add six.next() as an alias for six.advance_iterator().
+
+- Use the builtin next() function for advance_iterator() where is available
+  (2.6+), not just Python 3.
+
+- Add the Iterator class for writing portable iterators.
+
+1.1.0
+-----
+
+- Add the int2byte function.
+
+- Add compatibility mappings for iterators over the keys, values, and items of a
+  dictionary.
+
+- Fix six.MAXSIZE on platforms where sizeof(long) != sizeof(Py_ssize_t).
+
+- Issue #3: Add six.moves mappings for filter, map, and zip.
+
+1.0.0
+-----
+
+- Issue #2: u() on Python 2.x now resolves unicode escapes.
+
+- Expose an API for adding mappings to six.moves.
+
+1.0 beta 1
+----------
+
+- Reworked six into one .py file.  This breaks imports.  Please tell me if you
+  are interested in an import compatibility layer.
diff --git a/third_party/python/six/LICENSE b/third_party/python/six/LICENSE
new file mode 100644
index 0000000000..4b05a54526
--- /dev/null
+++ b/third_party/python/six/LICENSE
@@ -0,0 +1,18 @@
+Copyright (c) 2010-2019 Benjamin Peterson
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/third_party/python/six/MANIFEST.in b/third_party/python/six/MANIFEST.in
new file mode 100644
index 0000000000..b924e068ee
--- /dev/null
+++ b/third_party/python/six/MANIFEST.in
@@ -0,0 +1,6 @@
+include CHANGES
+include LICENSE
+include test_six.py
+
+recursive-include documentation *
+prune documentation/_build
diff --git a/third_party/python/six/PKG-INFO b/third_party/python/six/PKG-INFO
new file mode 100644
index 0000000000..33d8f432ea
--- /dev/null
+++ b/third_party/python/six/PKG-INFO
@@ -0,0 +1,50 @@
+Metadata-Version: 1.2
+Name: six
+Version: 1.13.0
+Summary: Python 2 and 3 compatibility utilities
+Home-page: https://github.com/benjaminp/six
+Author: Benjamin Peterson
+Author-email: benjamin@python.org
+License: MIT
+Description: .. image:: https://img.shields.io/pypi/v/six.svg
+           :target: https://pypi.org/project/six/
+           :alt: six on PyPI
+        
+        .. image:: https://travis-ci.org/benjaminp/six.svg?branch=master
+           :target: https://travis-ci.org/benjaminp/six
+           :alt: six on TravisCI
+        
+        .. image:: https://readthedocs.org/projects/six/badge/?version=latest
+           :target: https://six.readthedocs.io/
+           :alt: six's documentation on Read the Docs
+        
+        .. image:: https://img.shields.io/badge/license-MIT-green.svg
+           :target: https://github.com/benjaminp/six/blob/master/LICENSE
+           :alt: MIT License badge
+        
+        Six is a Python 2 and 3 compatibility library.  It provides utility functions
+        for smoothing over the differences between the Python versions with the goal of
+        writing Python code that is compatible on both Python versions.  See the
+        documentation for more information on what is provided.
+        
+        Six supports every Python version since 2.6.  It is contained in only one Python
+        file, so it can be easily copied into your project. (The copyright and license
+        notice must be retained.)
+        
+        Online documentation is at https://six.readthedocs.io/.
+        
+        Bugs can be reported to https://github.com/benjaminp/six.  The code can also
+        be found there.
+        
+        For questions about six or porting in general, email the python-porting mailing
+        list: https://mail.python.org/mailman/listinfo/python-porting
+        
+Platform: UNKNOWN
+Classifier: Development Status :: 5 - Production/Stable
+Classifier: Programming Language :: Python :: 2
+Classifier: Programming Language :: Python :: 3
+Classifier: Intended Audience :: Developers
+Classifier: License :: OSI Approved :: MIT License
+Classifier: Topic :: Software Development :: Libraries
+Classifier: Topic :: Utilities
+Requires-Python: >=2.6, !=3.0.*, !=3.1.*
diff --git a/third_party/python/six/README.rst b/third_party/python/six/README.rst
new file mode 100644
index 0000000000..a99e6f5585
--- /dev/null
+++ b/third_party/python/six/README.rst
@@ -0,0 +1,32 @@
+.. image:: https://img.shields.io/pypi/v/six.svg
+   :target: https://pypi.org/project/six/
+   :alt: six on PyPI
+
+.. image:: https://travis-ci.org/benjaminp/six.svg?branch=master
+   :target: https://travis-ci.org/benjaminp/six
+   :alt: six on TravisCI
+
+.. image:: https://readthedocs.org/projects/six/badge/?version=latest
+   :target: https://six.readthedocs.io/
+   :alt: six's documentation on Read the Docs
+
+.. image:: https://img.shields.io/badge/license-MIT-green.svg
+   :target: https://github.com/benjaminp/six/blob/master/LICENSE
+   :alt: MIT License badge
+
+Six is a Python 2 and 3 compatibility library.  It provides utility functions
+for smoothing over the differences between the Python versions with the goal of
+writing Python code that is compatible on both Python versions.  See the
+documentation for more information on what is provided.
+
+Six supports every Python version since 2.6.  It is contained in only one Python
+file, so it can be easily copied into your project. (The copyright and license
+notice must be retained.)
+
+Online documentation is at https://six.readthedocs.io/.
+
+Bugs can be reported to https://github.com/benjaminp/six.  The code can also
+be found there.
+
+For questions about six or porting in general, email the python-porting mailing
+list: https://mail.python.org/mailman/listinfo/python-porting
diff --git a/third_party/python/six/documentation/Makefile b/third_party/python/six/documentation/Makefile
new file mode 100644
index 0000000000..eebafcd6d6
--- /dev/null
+++ b/third_party/python/six/documentation/Makefile
@@ -0,0 +1,130 @@
+# Makefile for Sphinx documentation
+#
+
+# You can set these variables from the command line.
+SPHINXOPTS    =
+SPHINXBUILD   = sphinx-build
+PAPER         =
+BUILDDIR      = _build
+
+# Internal variables.
+PAPEROPT_a4     = -D latex_paper_size=a4
+PAPEROPT_letter = -D latex_paper_size=letter
+ALLSPHINXOPTS   = -d $(BUILDDIR)/doctrees $(PAPEROPT_$(PAPER)) $(SPHINXOPTS) .
+
+.PHONY: help clean html dirhtml singlehtml pickle json htmlhelp qthelp devhelp epub latex latexpdf text man changes linkcheck doctest
+
+help:
+	@echo "Please use \`make <target>' where <target> is one of"
+	@echo "  html       to make standalone HTML files"
+	@echo "  dirhtml    to make HTML files named index.html in directories"
+	@echo "  singlehtml to make a single large HTML file"
+	@echo "  pickle     to make pickle files"
+	@echo "  json       to make JSON files"
+	@echo "  htmlhelp   to make HTML files and a HTML help project"
+	@echo "  qthelp     to make HTML files and a qthelp project"
+	@echo "  devhelp    to make HTML files and a Devhelp project"
+	@echo "  epub       to make an epub"
+	@echo "  latex      to make LaTeX files, you can set PAPER=a4 or PAPER=letter"
+	@echo "  latexpdf   to make LaTeX files and run them through pdflatex"
+	@echo "  text       to make text files"
+	@echo "  man        to make manual pages"
+	@echo "  changes    to make an overview of all changed/added/deprecated items"
+	@echo "  linkcheck  to check all external links for integrity"
+	@echo "  doctest    to run all doctests embedded in the documentation (if enabled)"
+
+clean:
+	-rm -rf $(BUILDDIR)/*
+
+html:
+	$(SPHINXBUILD) -b html $(ALLSPHINXOPTS) $(BUILDDIR)/html
+	@echo
+	@echo "Build finished. The HTML pages are in $(BUILDDIR)/html."
+
+dirhtml:
+	$(SPHINXBUILD) -b dirhtml $(ALLSPHINXOPTS) $(BUILDDIR)/dirhtml
+	@echo
+	@echo "Build finished. The HTML pages are in $(BUILDDIR)/dirhtml."
+
+singlehtml:
+	$(SPHINXBUILD) -b singlehtml $(ALLSPHINXOPTS) $(BUILDDIR)/singlehtml
+	@echo
+	@echo "Build finished. The HTML page is in $(BUILDDIR)/singlehtml."
+
+pickle:
+	$(SPHINXBUILD) -b pickle $(ALLSPHINXOPTS) $(BUILDDIR)/pickle
+	@echo
+	@echo "Build finished; now you can process the pickle files."
+
+json:
+	$(SPHINXBUILD) -b json $(ALLSPHINXOPTS) $(BUILDDIR)/json
+	@echo
+	@echo "Build finished; now you can process the JSON files."
+
+htmlhelp:
+	$(SPHINXBUILD) -b htmlhelp $(ALLSPHINXOPTS) $(BUILDDIR)/htmlhelp
+	@echo
+	@echo "Build finished; now you can run HTML Help Workshop with the" \
+	      ".hhp project file in $(BUILDDIR)/htmlhelp."
+
+qthelp:
+	$(SPHINXBUILD) -b qthelp $(ALLSPHINXOPTS) $(BUILDDIR)/qthelp
+	@echo
+	@echo "Build finished; now you can run "qcollectiongenerator" with the" \
+	      ".qhcp project file in $(BUILDDIR)/qthelp, like this:"
+	@echo "# qcollectiongenerator $(BUILDDIR)/qthelp/six.qhcp"
+	@echo "To view the help file:"
+	@echo "# assistant -collectionFile $(BUILDDIR)/qthelp/six.qhc"
+
+devhelp:
+	$(SPHINXBUILD) -b devhelp $(ALLSPHINXOPTS) $(BUILDDIR)/devhelp
+	@echo
+	@echo "Build finished."
+	@echo "To view the help file:"
+	@echo "# mkdir -p $$HOME/.local/share/devhelp/six"
+	@echo "# ln -s $(BUILDDIR)/devhelp $$HOME/.local/share/devhelp/six"
+	@echo "# devhelp"
+
+epub:
+	$(SPHINXBUILD) -b epub $(ALLSPHINXOPTS) $(BUILDDIR)/epub
+	@echo
+	@echo "Build finished. The epub file is in $(BUILDDIR)/epub."
+
+latex:
+	$(SPHINXBUILD) -b latex $(ALLSPHINXOPTS) $(BUILDDIR)/latex
+	@echo
+	@echo "Build finished; the LaTeX files are in $(BUILDDIR)/latex."
+	@echo "Run \`make' in that directory to run these through (pdf)latex" \
+	      "(use \`make latexpdf' here to do that automatically)."
+
+latexpdf:
+	$(SPHINXBUILD) -b latex $(ALLSPHINXOPTS) $(BUILDDIR)/latex
+	@echo "Running LaTeX files through pdflatex..."
+	make -C $(BUILDDIR)/latex all-pdf
+	@echo "pdflatex finished; the PDF files are in $(BUILDDIR)/latex."
+
+text:
+	$(SPHINXBUILD) -b text $(ALLSPHINXOPTS) $(BUILDDIR)/text
+	@echo
+	@echo "Build finished. The text files are in $(BUILDDIR)/text."
+
+man:
+	$(SPHINXBUILD) -b man $(ALLSPHINXOPTS) $(BUILDDIR)/man
+	@echo
+	@echo "Build finished. The manual pages are in $(BUILDDIR)/man."
+
+changes:
+	$(SPHINXBUILD) -b changes $(ALLSPHINXOPTS) $(BUILDDIR)/changes
+	@echo
+	@echo "The overview file is in $(BUILDDIR)/changes."
+
+linkcheck:
+	$(SPHINXBUILD) -b linkcheck $(ALLSPHINXOPTS) $(BUILDDIR)/linkcheck
+	@echo
+	@echo "Link check complete; look for any errors in the above output " \
+	      "or in $(BUILDDIR)/linkcheck/output.txt."
+
+doctest:
+	$(SPHINXBUILD) -b doctest $(ALLSPHINXOPTS) $(BUILDDIR)/doctest
+	@echo "Testing of doctests in the sources finished, look at the " \
+	      "results in $(BUILDDIR)/doctest/output.txt."
diff --git a/third_party/python/six/documentation/conf.py b/third_party/python/six/documentation/conf.py
new file mode 100644
index 0000000000..b3d1328adc
--- /dev/null
+++ b/third_party/python/six/documentation/conf.py
@@ -0,0 +1,217 @@
+# -*- coding: utf-8 -*-
+#
+# six documentation build configuration file
+
+import os
+import sys
+
+# If extensions (or modules to document with autodoc) are in another directory,
+# add these directories to sys.path here. If the directory is relative to the
+# documentation root, use os.path.abspath to make it absolute, like shown here.
+#sys.path.append(os.path.abspath('.'))
+
+# -- General configuration -----------------------------------------------------
+
+# If your documentation needs a minimal Sphinx version, state it here.
+needs_sphinx = "1.0"
+
+# Add any Sphinx extension module names here, as strings. They can be extensions
+# coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
+extensions = ["sphinx.ext.intersphinx"]
+
+# Add any paths that contain templates here, relative to this directory.
+templates_path = ["_templates"]
+
+# The suffix of source filenames.
+source_suffix = ".rst"
+
+# The encoding of source files.
+#source_encoding = "utf-8-sig"
+
+# The master toctree document.
+master_doc = "index"
+
+# General information about the project.
+project = u"six"
+copyright = u"2010-2019, Benjamin Peterson"
+
+sys.path.append(os.path.abspath(os.path.join(".", "..")))
+from six import __version__ as six_version
+sys.path.pop()
+
+# The version info for the project you're documenting, acts as replacement for
+# |version| and |release|, also used in various other places throughout the
+# built documents.
+#
+# The short X.Y version.
+version = six_version[:-2]
+# The full version, including alpha/beta/rc tags.
+release = six_version
+
+# The language for content autogenerated by Sphinx. Refer to documentation
+# for a list of supported languages.
+#language = None
+
+# There are two options for replacing |today|: either, you set today to some
+# non-false value, then it is used:
+#today = ''
+# Else, today_fmt is used as the format for a strftime call.
+#today_fmt = '%B %d, %Y'
+
+# List of patterns, relative to source directory, that match files and
+# directories to ignore when looking for source files.
+exclude_patterns = ["_build"]
+
+# The reST default role (used for this markup: `text`) to use for all documents.
+#default_role = None
+
+# If true, '()' will be appended to :func: etc. cross-reference text.
+#add_function_parentheses = True
+
+# If true, the current module name will be prepended to all description
+# unit titles (such as .. function::).
+#add_module_names = True
+
+# If true, sectionauthor and moduleauthor directives will be shown in the
+# output. They are ignored by default.
+#show_authors = False
+
+# The name of the Pygments (syntax highlighting) style to use.
+pygments_style = "sphinx"
+
+# A list of ignored prefixes for module index sorting.
+#modindex_common_prefix = []
+
+
+# -- Options for HTML output ---------------------------------------------------
+
+# The theme to use for HTML and HTML Help pages.  See the documentation for
+# a list of builtin themes.
+html_theme = "default"
+
+# Theme options are theme-specific and customize the look and feel of a theme
+# further.  For a list of options available for each theme, see the
+# documentation.
+#html_theme_options = {}
+
+# Add any paths that contain custom themes here, relative to this directory.
+#html_theme_path = []
+
+# The name for this set of Sphinx documents.  If None, it defaults to
+# "<project> v<release> documentation".
+#html_title = None
+
+# A shorter title for the navigation bar.  Default is the same as html_title.
+#html_short_title = None
+
+# The name of an image file (relative to this directory) to place at the top
+# of the sidebar.
+#html_logo = None
+
+# The name of an image file (within the static path) to use as favicon of the
+# docs.  This file should be a Windows icon file (.ico) being 16x16 or 32x32
+# pixels large.
+#html_favicon = None
+
+# Add any paths that contain custom static files (such as style sheets) here,
+# relative to this directory. They are copied after the builtin static files,
+# so a file named "default.css" will overwrite the builtin "default.css".
+html_static_path = ["_static"]
+
+# If not '', a 'Last updated on:' timestamp is inserted at every page bottom,
+# using the given strftime format.
+#html_last_updated_fmt = '%b %d, %Y'
+
+# If true, SmartyPants will be used to convert quotes and dashes to
+# typographically correct entities.
+#html_use_smartypants = True
+
+# Custom sidebar templates, maps document names to template names.
+#html_sidebars = {}
+
+# Additional templates that should be rendered to pages, maps page names to
+# template names.
+#html_additional_pages = {}
+
+# If false, no module index is generated.
+#html_domain_indices = True
+
+# If false, no index is generated.
+#html_use_index = True
+
+# If true, the index is split into individual pages for each letter.
+#html_split_index = False
+
+# If true, links to the reST sources are added to the pages.
+#html_show_sourcelink = True
+
+# If true, "Created using Sphinx" is shown in the HTML footer. Default is True.
+#html_show_sphinx = True
+
+# If true, "(C) Copyright ..." is shown in the HTML footer. Default is True.
+#html_show_copyright = True
+
+# If true, an OpenSearch description file will be output, and all pages will
+# contain a <link> tag referring to it.  The value of this option must be the
+# base URL from which the finished HTML is served.
+#html_use_opensearch = ''
+
+# If nonempty, this is the file name suffix for HTML files (e.g. ".xhtml").
+#html_file_suffix = ''
+
+# Output file base name for HTML help builder.
+htmlhelp_basename = 'sixdoc'
+
+
+# -- Options for LaTeX output --------------------------------------------------
+
+# The paper size ('letter' or 'a4').
+#latex_paper_size = 'letter'
+
+# The font size ('10pt', '11pt' or '12pt').
+#latex_font_size = '10pt'
+
+# Grouping the document tree into LaTeX files. List of tuples
+# (source start file, target name, title, author, documentclass [howto/manual]).
+latex_documents = [
+  ("index", "six.tex", u"six Documentation",
+   u"Benjamin Peterson", "manual"),
+]
+
+# The name of an image file (relative to this directory) to place at the top of
+# the title page.
+#latex_logo = None
+
+# For "manual" documents, if this is true, then toplevel headings are parts,
+# not chapters.
+#latex_use_parts = False
+
+# If true, show page references after internal links.
+#latex_show_pagerefs = False
+
+# If true, show URL addresses after external links.
+#latex_show_urls = False
+
+# Additional stuff for the LaTeX preamble.
+#latex_preamble = ''
+
+# Documents to append as an appendix to all manuals.
+#latex_appendices = []
+
+# If false, no module index is generated.
+#latex_domain_indices = True
+
+
+# -- Options for manual page output --------------------------------------------
+
+# One entry per manual page. List of tuples
+# (source start file, name, description, authors, manual section).
+man_pages = [
+    ("index", "six", u"six Documentation",
+     [u"Benjamin Peterson"], 1)
+]
+
+# -- Intersphinx ---------------------------------------------------------------
+
+intersphinx_mapping = {"py2" : ("https://docs.python.org/2/", None),
+                       "py3" : ("https://docs.python.org/3/", None)}
diff --git a/third_party/python/six/documentation/index.rst b/third_party/python/six/documentation/index.rst
new file mode 100644
index 0000000000..b7ec2754ec
--- /dev/null
+++ b/third_party/python/six/documentation/index.rst
@@ -0,0 +1,875 @@
+Six: Python 2 and 3 Compatibility Library
+=========================================
+
+.. module:: six
+   :synopsis: Python 2 and 3 compatibility
+
+.. moduleauthor:: Benjamin Peterson <benjamin@python.org>
+.. sectionauthor:: Benjamin Peterson <benjamin@python.org>
+
+
+Six provides simple utilities for wrapping over differences between Python 2 and
+Python 3.  It is intended to support codebases that work on both Python 2 and 3
+without modification.  six consists of only one Python file, so it is painless
+to copy into a project.
+
+Six can be downloaded on `PyPI <https://pypi.org/project/six/>`_.  Its bug
+tracker and code hosting is on `GitHub <https://github.com/benjaminp/six>`_.
+
+The name, "six", comes from the fact that 2*3 equals 6.  Why not addition?
+Multiplication is more powerful, and, anyway, "five" has already been snatched
+away by the (admittedly now moribund) Zope Five project.
+
+
+Indices and tables
+------------------
+
+* :ref:`genindex`
+* :ref:`search`
+
+
+Package contents
+----------------
+
+.. data:: PY2
+
+   A boolean indicating if the code is running on Python 2.
+
+.. data:: PY3
+
+   A boolean indicating if the code is running on Python 3.
+
+
+Constants
+>>>>>>>>>
+
+Six provides constants that may differ between Python versions.  Ones ending
+``_types`` are mostly useful as the second argument to ``isinstance`` or
+``issubclass``.
+
+
+.. data:: class_types
+
+   Possible class types.  In Python 2, this encompasses old-style
+   :data:`py2:types.ClassType` and new-style ``type`` classes.  In Python 3,
+   this is just ``type``.
+
+
+.. data:: integer_types
+
+   Possible integer types.  In Python 2, this is :func:`py2:long` and
+   :func:`py2:int`, and in Python 3, just :func:`py3:int`.
+
+
+.. data:: string_types
+
+   Possible types for text data.  This is :func:`py2:basestring` in Python 2 and
+   :func:`py3:str` in Python 3.
+
+
+.. data:: text_type
+
+   Type for representing (Unicode) textual data.  This is :func:`py2:unicode` in
+   Python 2 and :func:`py3:str` in Python 3.
+
+
+.. data:: binary_type
+
+   Type for representing binary data.  This is :func:`py2:str` in Python 2 and
+   :func:`py3:bytes` in Python 3.  Python 2.6 and 2.7 include ``bytes`` as a
+   builtin alias of ``str``, so six’s version is only necessary for Python 2.5
+   compatibility.
+
+
+.. data:: MAXSIZE
+
+   The maximum  size of a  container like :func:`py3:list`  or :func:`py3:dict`.
+   This  is  equivalent  to  :data:`py3:sys.maxsize` in  Python  2.6  and  later
+   (including 3.x).   Note, this is temptingly  similar to, but not  the same as
+   :data:`py2:sys.maxint`  in  Python  2.   There is  no  direct  equivalent  to
+   :data:`py2:sys.maxint` in  Python 3  because its integer  type has  no limits
+   aside from memory.
+
+
+Here's example usage of the module::
+
+   import six
+
+   def dispatch_types(value):
+       if isinstance(value, six.integer_types):
+           handle_integer(value)
+       elif isinstance(value, six.class_types):
+           handle_class(value)
+       elif isinstance(value, six.string_types):
+           handle_string(value)
+
+
+Object model compatibility
+>>>>>>>>>>>>>>>>>>>>>>>>>>
+
+Python 3 renamed the attributes of several interpreter data structures.  The
+following accessors are available.  Note that the recommended way to inspect
+functions and methods is the stdlib :mod:`py3:inspect` module.
+
+
+.. function:: get_unbound_function(meth)
+
+   Get the function out of unbound method *meth*.  In Python 3, unbound methods
+   don't exist, so this function just returns *meth* unchanged.  Example
+   usage::
+
+      from six import get_unbound_function
+
+      class X(object):
+          def method(self):
+              pass
+      method_function = get_unbound_function(X.method)
+
+
+.. function:: get_method_function(meth)
+
+   Get the function out of method object *meth*.
+
+
+.. function:: get_method_self(meth)
+
+   Get the ``self`` of bound method *meth*.
+
+
+.. function:: get_function_closure(func)
+
+   Get the closure (list of cells) associated with *func*.  This is equivalent
+   to ``func.__closure__`` on Python 2.6+ and ``func.func_closure`` on Python
+   2.5.
+
+
+.. function:: get_function_code(func)
+
+   Get the code object associated with *func*.  This is equivalent to
+   ``func.__code__`` on Python 2.6+ and ``func.func_code`` on Python 2.5.
+
+
+.. function:: get_function_defaults(func)
+
+   Get the defaults tuple associated with *func*.  This is equivalent to
+   ``func.__defaults__`` on Python 2.6+ and ``func.func_defaults`` on Python
+   2.5.
+
+
+.. function:: get_function_globals(func)
+
+   Get the globals of *func*.  This is equivalent to ``func.__globals__`` on
+   Python 2.6+ and ``func.func_globals`` on Python 2.5.
+
+
+.. function:: next(it)
+              advance_iterator(it)
+
+   Get the next item of iterator *it*.  :exc:`py3:StopIteration` is raised if
+   the iterator is exhausted.  This is a replacement for calling ``it.next()``
+   in Python 2 and ``next(it)`` in Python 3.  Python 2.6 and above have a
+   builtin ``next`` function, so six's version is only necessary for Python 2.5
+   compatibility.
+
+
+.. function:: callable(obj)
+
+   Check if *obj* can be called.  Note ``callable`` has returned in Python 3.2,
+   so using six's version is only necessary when supporting Python 3.0 or 3.1.
+
+
+.. function:: iterkeys(dictionary, **kwargs)
+
+   Returns an iterator over *dictionary*\'s keys. This replaces
+   ``dictionary.iterkeys()`` on Python 2 and ``dictionary.keys()`` on
+   Python 3.  *kwargs* are passed through to the underlying method.
+
+
+.. function:: itervalues(dictionary, **kwargs)
+
+   Returns an iterator over *dictionary*\'s values. This replaces
+   ``dictionary.itervalues()`` on Python 2 and ``dictionary.values()`` on
+   Python 3.  *kwargs* are passed through to the underlying method.
+
+
+.. function:: iteritems(dictionary, **kwargs)
+
+   Returns an iterator over *dictionary*\'s items. This replaces
+   ``dictionary.iteritems()`` on Python 2 and ``dictionary.items()`` on
+   Python 3.  *kwargs* are passed through to the underlying method.
+
+
+.. function:: iterlists(dictionary, **kwargs)
+
+   Calls ``dictionary.iterlists()`` on Python 2 and ``dictionary.lists()`` on
+   Python 3.  No builtin Python mapping type has such a method; this method is
+   intended for use with multi-valued dictionaries like `Werkzeug's
+   <http://werkzeug.pocoo.org/docs/datastructures/#werkzeug.datastructures.MultiDict>`_.
+   *kwargs* are passed through to the underlying method.
+
+
+.. function:: viewkeys(dictionary)
+
+   Return a view over *dictionary*\'s keys. This replaces
+   :meth:`py2:dict.viewkeys` on Python 2.7 and :meth:`py3:dict.keys` on
+   Python 3.
+
+
+.. function:: viewvalues(dictionary)
+
+   Return a view over *dictionary*\'s values. This replaces
+   :meth:`py2:dict.viewvalues` on Python 2.7 and :meth:`py3:dict.values` on
+   Python 3.
+
+
+.. function:: viewitems(dictionary)
+
+   Return a view over *dictionary*\'s items. This replaces
+   :meth:`py2:dict.viewitems` on Python 2.7 and :meth:`py3:dict.items` on
+   Python 3.
+
+
+.. function:: create_bound_method(func, obj)
+
+   Return a method object wrapping *func* and bound to *obj*.  On both Python 2
+   and 3, this will return a :func:`py3:types.MethodType` object.  The reason
+   this wrapper exists is that on Python 2, the ``MethodType`` constructor
+   requires the *obj*'s class to be passed.
+
+
+.. function:: create_unbound_method(func, cls)
+
+   Return an unbound method object wrapping *func*.  In Python 2, this will
+   return a :func:`py2:types.MethodType` object.  In Python 3, unbound methods
+   do not exist and this wrapper will simply return *func*.
+
+
+.. class:: Iterator
+
+   A class for making portable iterators. The intention is that it be subclassed
+   and subclasses provide a ``__next__`` method. In Python 2, :class:`Iterator`
+   has one method: ``next``. It simply delegates to ``__next__``. An alternate
+   way to do this would be to simply alias ``next`` to ``__next__``. However,
+   this interacts badly with subclasses that override
+   ``__next__``. :class:`Iterator` is empty on Python 3. (In fact, it is just
+   aliased to :class:`py3:object`.)
+
+
+.. decorator:: wraps(wrapped, assigned=functools.WRAPPER_ASSIGNMENTS, updated=functools.WRAPPER_UPDATES)
+
+   This is exactly the :func:`py3:functools.wraps` decorator, but it sets the
+   ``__wrapped__`` attribute on what it decorates as :func:`py3:functools.wraps`
+   does on Python versions after 3.2.
+
+
+Syntax compatibility
+>>>>>>>>>>>>>>>>>>>>
+
+These functions smooth over operations which have different syntaxes between
+Python 2 and 3.
+
+
+.. function:: exec_(code, globals=None, locals=None)
+
+   Execute *code* in the scope of *globals* and *locals*.  *code* can be a
+   string or a code object.  If *globals* or *locals* are not given, they will
+   default to the scope of the caller.  If just *globals* is given, it will also
+   be used as *locals*.
+
+   .. note::
+
+      Python 3's :func:`py3:exec` doesn't take keyword arguments, so calling
+      :func:`exec` with them should be avoided.
+
+
+.. function:: print_(*args, *, file=sys.stdout, end="\\n", sep=" ", flush=False)
+
+   Print *args* into *file*.  Each argument will be separated with *sep* and
+   *end* will be written to the file after the last argument is printed.  If
+   *flush* is true, ``file.flush()`` will be called after all data is written.
+
+   .. note::
+
+      In Python 2, this function imitates Python 3's :func:`py3:print` by not
+      having softspace support.  If you don't know what that is, you're probably
+      ok. :)
+
+
+.. function:: raise_from(exc_value, exc_value_from)
+
+   Raise an exception from a context.  On Python 3, this is equivalent to
+   ``raise exc_value from exc_value_from``.  On Python 2, which does not support
+   exception chaining, it is equivalent to ``raise exc_value``.
+
+
+.. function:: reraise(exc_type, exc_value, exc_traceback=None)
+
+   Reraise an exception, possibly with a different traceback.  In the simple
+   case, ``reraise(*sys.exc_info())`` with an active exception (in an except
+   block) reraises the current exception with the last traceback.  A different
+   traceback can be specified with the *exc_traceback* parameter.  Note that
+   since the exception reraising is done within the :func:`reraise` function,
+   Python will attach the call frame of :func:`reraise` to whatever traceback is
+   raised.
+
+
+.. function:: with_metaclass(metaclass, *bases)
+
+   Create a new class with base classes *bases* and metaclass *metaclass*.  This
+   is designed to be used in class declarations like this: ::
+
+      from six import with_metaclass
+
+      class Meta(type):
+          pass
+
+      class Base(object):
+          pass
+
+      class MyClass(with_metaclass(Meta, Base)):
+          pass
+
+   Another way to set a metaclass on a class is with the :func:`add_metaclass`
+   decorator.
+
+
+.. decorator:: add_metaclass(metaclass)
+
+   Class decorator that replaces a normally-constructed class with a
+   metaclass-constructed one.  Example usage: ::
+
+       @add_metaclass(Meta)
+       class MyClass(object):
+           pass
+
+   That code produces a class equivalent to ::
+
+       class MyClass(object, metaclass=Meta):
+           pass
+
+   on Python 3 or ::
+
+       class MyClass(object):
+           __metaclass__ = Meta
+
+   on Python 2.
+
+   Note that class decorators require Python 2.6. However, the effect of the
+   decorator can be emulated on Python 2.5 like so::
+
+       class MyClass(object):
+           pass
+       MyClass = add_metaclass(Meta)(MyClass)
+
+
+Binary and text data
+>>>>>>>>>>>>>>>>>>>>
+
+Python 3 enforces the distinction between byte strings and text strings far more
+rigorously than Python 2 does; binary data cannot be automatically coerced to
+or from text data.  six provides several functions to assist in classifying
+string data in all Python versions.
+
+
+.. function:: b(data)
+
+   A "fake" bytes literal.  *data* should always be a normal string literal.  In
+   Python 2, :func:`b` returns an 8-bit string.  In Python 3, *data* is encoded
+   with the latin-1 encoding to bytes.
+
+
+   .. note::
+
+      Since all Python versions 2.6 and after support the ``b`` prefix,
+      code without 2.5 support doesn't need :func:`b`.
+
+
+.. function:: u(text)
+
+   A "fake" unicode literal.  *text* should always be a normal string literal.
+   In Python 2, :func:`u` returns unicode, and in Python 3, a string.  Also, in
+   Python 2, the string is decoded with the ``unicode-escape`` codec, which
+   allows unicode escapes to be used in it.
+
+
+   .. note::
+
+      In Python 3.3, the ``u`` prefix has been reintroduced. Code that only
+      supports Python 3 versions of 3.3 and higher thus does not need
+      :func:`u`.
+
+   .. note::
+
+      On Python 2, :func:`u` doesn't know what the encoding of the literal
+      is. Each byte is converted directly to the unicode codepoint of the same
+      value. Because of this, it's only safe to use :func:`u` with strings of
+      ASCII data.
+
+
+.. function:: unichr(c)
+
+   Return the (Unicode) string representing the codepoint *c*.  This is
+   equivalent to :func:`py2:unichr` on Python 2 and :func:`py3:chr` on Python 3.
+
+
+.. function:: int2byte(i)
+
+   Converts *i* to a byte.  *i* must be in ``range(0, 256)``.  This is
+   equivalent to :func:`py2:chr` in Python 2 and ``bytes((i,))`` in Python 3.
+
+
+.. function:: byte2int(bs)
+
+   Converts the first byte of *bs* to an integer.  This is equivalent to
+   ``ord(bs[0])`` on Python 2 and ``bs[0]`` on Python 3.
+
+
+.. function:: indexbytes(buf, i)
+
+   Return the byte at index *i* of *buf* as an integer.  This is equivalent to
+   indexing a bytes object in Python 3.
+
+
+.. function:: iterbytes(buf)
+
+   Return an iterator over bytes in *buf* as integers.  This is equivalent to
+   a bytes object iterator in Python 3.
+
+
+.. function:: ensure_binary(s, encoding='utf-8', errors='strict')
+
+   Coerce *s* to :data:`binary_type`. *encoding*, *errors* are the same as
+   :meth:`py3:str.encode`
+
+
+.. function:: ensure_str(s, encoding='utf-8', errors='strict')
+
+   Coerce *s* to ``str``. *encoding*, *errors* are the same as
+   :meth:`py3:str.encode`
+
+
+.. function:: ensure_text(s, encoding='utf-8', errors='strict')
+
+   Coerce *s* to :data:`text_type`. *encoding*, *errors* are the same as
+   :meth:`py3:str.encode`
+
+
+.. data:: StringIO
+
+   This is a fake file object for textual data.  It's an alias for
+   :class:`py2:StringIO.StringIO` in Python 2 and :class:`py3:io.StringIO` in
+   Python 3.
+
+
+.. data:: BytesIO
+
+   This is a fake file object for binary data.  In Python 2, it's an alias for
+   :class:`py2:StringIO.StringIO`, but in Python 3, it's an alias for
+   :class:`py3:io.BytesIO`.
+
+
+.. decorator:: python_2_unicode_compatible
+
+   A class decorator that takes a class defining a ``__str__`` method.  On
+   Python 3, the decorator does nothing.  On Python 2, it aliases the
+   ``__str__`` method to ``__unicode__`` and creates a new ``__str__`` method
+   that returns the result of ``__unicode__()`` encoded with UTF-8.
+
+
+unittest assertions
+>>>>>>>>>>>>>>>>>>>
+
+Six contains compatibility shims for unittest assertions that have been renamed.
+The parameters are the same as their aliases, but you must pass the test method
+as the first argument. For example::
+
+    import six
+    import unittest
+
+    class TestAssertCountEqual(unittest.TestCase):
+        def test(self):
+            six.assertCountEqual(self, (1, 2), [2, 1])
+
+Note these functions are only available on Python 2.7 or later.
+
+.. function:: assertCountEqual()
+
+   Alias for :meth:`~py3:unittest.TestCase.assertCountEqual` on Python 3 and
+   :meth:`~py2:unittest.TestCase.assertItemsEqual` on Python 2.
+
+
+.. function:: assertRaisesRegex()
+
+   Alias for :meth:`~py3:unittest.TestCase.assertRaisesRegex` on Python 3 and
+   :meth:`~py2:unittest.TestCase.assertRaisesRegexp` on Python 2.
+
+
+.. function:: assertRegex()
+
+   Alias for :meth:`~py3:unittest.TestCase.assertRegex` on Python 3 and
+   :meth:`~py2:unittest.TestCase.assertRegexpMatches` on Python 2.
+
+
+Renamed modules and attributes compatibility
+>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
+
+.. module:: six.moves
+   :synopsis: Renamed modules and attributes compatibility
+
+Python 3 reorganized the standard library and moved several functions to
+different modules.  Six provides a consistent interface to them through the fake
+:mod:`six.moves` module.  For example, to load the module for parsing HTML on
+Python 2 or 3, write::
+
+   from six.moves import html_parser
+
+Similarly, to get the function to reload modules, which was moved from the
+builtin module to the ``importlib`` module, use::
+
+   from six.moves import reload_module
+
+For the most part, :mod:`six.moves` aliases are the names of the modules in
+Python 3.  When the new Python 3 name is a package, the components of the name
+are separated by underscores.  For example, ``html.parser`` becomes
+``html_parser``.  In some cases where several modules have been combined, the
+Python 2 name is retained.  This is so the appropriate modules can be found when
+running on Python 2.  For example, ``BaseHTTPServer`` which is in
+``http.server`` in Python 3 is aliased as ``BaseHTTPServer``.
+
+Some modules which had two implementations have been merged in Python 3.  For
+example, ``cPickle`` no longer exists in Python 3; it was merged with
+``pickle``.  In these cases, fetching the fast version will load the fast one on
+Python 2 and the merged module in Python 3.
+
+The :mod:`py2:urllib`, :mod:`py2:urllib2`, and :mod:`py2:urlparse` modules have
+been combined in the :mod:`py3:urllib` package in Python 3.  The
+:mod:`six.moves.urllib` package is a version-independent location for this
+functionality; its structure mimics the structure of the Python 3
+:mod:`py3:urllib` package.
+
+.. note::
+
+   In order to make imports of the form::
+
+     from six.moves.cPickle import loads
+
+   work, six places special proxy objects in :data:`py3:sys.modules`. These
+   proxies lazily load the underlying module when an attribute is fetched. This
+   will fail if the underlying module is not available in the Python
+   interpreter. For example, ``sys.modules["six.moves.winreg"].LoadKey`` would
+   fail on any non-Windows platform. Unfortunately, some applications try to
+   load attributes on every module in :data:`py3:sys.modules`. six mitigates
+   this problem for some applications by pretending attributes on unimportable
+   modules do not exist. This hack does not work in every case, though. If you are
+   encountering problems with the lazy modules and don't use any from imports
+   directly from ``six.moves`` modules, you can workaround the issue by removing
+   the six proxy modules::
+
+     d = [name for name in sys.modules if name.startswith("six.moves.")]
+     for name in d:
+         del sys.modules[name]
+
+Supported renames:
+
++------------------------------+-------------------------------------+---------------------------------------+
+| Name                         | Python 2 name                       | Python 3 name                         |
++==============================+=====================================+=======================================+
+| ``builtins``                 | :mod:`py2:__builtin__`              | :mod:`py3:builtins`                   |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``configparser``             | :mod:`py2:ConfigParser`             | :mod:`py3:configparser`               |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``copyreg``                  | :mod:`py2:copy_reg`                 | :mod:`py3:copyreg`                    |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``cPickle``                  | :mod:`py2:cPickle`                  | :mod:`py3:pickle`                     |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``cStringIO``                | :func:`py2:cStringIO.StringIO`      | :class:`py3:io.StringIO`              |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``collections_abc``          | :mod:`py2:collections`              | :mod:`py3:collections.abc` (3.3+)     |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``dbm_gnu``                  | :mod:`py2:gdbm`                     | :mod:`py3:dbm.gnu`                    |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``dbm_ndbm``                 | :mod:`py2:dbm`                      | :mod:`py3:dbm.ndbm`                   |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``_dummy_thread``            | :mod:`py2:dummy_thread`             | :mod:`py3:_dummy_thread`              |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``email_mime_base``          | :mod:`py2:email.MIMEBase`           | :mod:`py3:email.mime.base`            |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``email_mime_image``         | :mod:`py2:email.MIMEImage`          | :mod:`py3:email.mime.image`           |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``email_mime_multipart``     | :mod:`py2:email.MIMEMultipart`      | :mod:`py3:email.mime.multipart`       |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``email_mime_nonmultipart``  | :mod:`py2:email.MIMENonMultipart`   | :mod:`py3:email.mime.nonmultipart`    |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``email_mime_text``          | :mod:`py2:email.MIMEText`           | :mod:`py3:email.mime.text`            |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``filter``                   | :func:`py2:itertools.ifilter`       | :func:`py3:filter`                    |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``filterfalse``              | :func:`py2:itertools.ifilterfalse`  | :func:`py3:itertools.filterfalse`     |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``getcwd``                   | :func:`py2:os.getcwdu`              | :func:`py3:os.getcwd`                 |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``getcwdb``                  | :func:`py2:os.getcwd`               | :func:`py3:os.getcwdb`                |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``getoutput``                | :func:`py2:commands.getoutput`      | :func:`py3:subprocess.getoutput`      |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``http_cookiejar``           | :mod:`py2:cookielib`                | :mod:`py3:http.cookiejar`             |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``http_cookies``             | :mod:`py2:Cookie`                   | :mod:`py3:http.cookies`               |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``html_entities``            | :mod:`py2:htmlentitydefs`           | :mod:`py3:html.entities`              |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``html_parser``              | :mod:`py2:HTMLParser`               | :mod:`py3:html.parser`                |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``http_client``              | :mod:`py2:httplib`                  | :mod:`py3:http.client`                |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``BaseHTTPServer``           | :mod:`py2:BaseHTTPServer`           | :mod:`py3:http.server`                |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``CGIHTTPServer``            | :mod:`py2:CGIHTTPServer`            | :mod:`py3:http.server`                |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``SimpleHTTPServer``         | :mod:`py2:SimpleHTTPServer`         | :mod:`py3:http.server`                |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``input``                    | :func:`py2:raw_input`               | :func:`py3:input`                     |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``intern``                   | :func:`py2:intern`                  | :func:`py3:sys.intern`                |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``map``                      | :func:`py2:itertools.imap`          | :func:`py3:map`                       |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``queue``                    | :mod:`py2:Queue`                    | :mod:`py3:queue`                      |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``range``                    | :func:`py2:xrange`                  | :func:`py3:range`                     |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``reduce``                   | :func:`py2:reduce`                  | :func:`py3:functools.reduce`          |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``reload_module``            | :func:`py2:reload`                  | :func:`py3:imp.reload`,               |
+|                              |                                     | :func:`py3:importlib.reload`          |
+|                              |                                     | on Python 3.4+                        |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``reprlib``                  | :mod:`py2:repr`                     | :mod:`py3:reprlib`                    |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``shlex_quote``              | :mod:`py2:pipes.quote`              | :mod:`py3:shlex.quote`                |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``socketserver``             | :mod:`py2:SocketServer`             | :mod:`py3:socketserver`               |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``_thread``                  | :mod:`py2:thread`                   | :mod:`py3:_thread`                    |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``tkinter``                  | :mod:`py2:Tkinter`                  | :mod:`py3:tkinter`                    |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``tkinter_dialog``           | :mod:`py2:Dialog`                   | :mod:`py3:tkinter.dialog`             |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``tkinter_filedialog``       | :mod:`py2:FileDialog`               | :mod:`py3:tkinter.FileDialog`         |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``tkinter_scrolledtext``     | :mod:`py2:ScrolledText`             | :mod:`py3:tkinter.scrolledtext`       |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``tkinter_simpledialog``     | :mod:`py2:SimpleDialog`             | :mod:`py3:tkinter.simpledialog`       |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``tkinter_ttk``              | :mod:`py2:ttk`                      | :mod:`py3:tkinter.ttk`                |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``tkinter_tix``              | :mod:`py2:Tix`                      | :mod:`py3:tkinter.tix`                |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``tkinter_constants``        | :mod:`py2:Tkconstants`              | :mod:`py3:tkinter.constants`          |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``tkinter_dnd``              | :mod:`py2:Tkdnd`                    | :mod:`py3:tkinter.dnd`                |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``tkinter_colorchooser``     | :mod:`py2:tkColorChooser`           | :mod:`py3:tkinter.colorchooser`       |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``tkinter_commondialog``     | :mod:`py2:tkCommonDialog`           | :mod:`py3:tkinter.commondialog`       |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``tkinter_tkfiledialog``     | :mod:`py2:tkFileDialog`             | :mod:`py3:tkinter.filedialog`         |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``tkinter_font``             | :mod:`py2:tkFont`                   | :mod:`py3:tkinter.font`               |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``tkinter_messagebox``       | :mod:`py2:tkMessageBox`             | :mod:`py3:tkinter.messagebox`         |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``tkinter_tksimpledialog``   | :mod:`py2:tkSimpleDialog`           | :mod:`py3:tkinter.simpledialog`       |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``urllib.parse``             | See :mod:`six.moves.urllib.parse`   | :mod:`py3:urllib.parse`               |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``urllib.error``             | See :mod:`six.moves.urllib.error`   | :mod:`py3:urllib.error`               |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``urllib.request``           | See :mod:`six.moves.urllib.request` | :mod:`py3:urllib.request`             |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``urllib.response``          | See :mod:`six.moves.urllib.response`| :mod:`py3:urllib.response`            |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``urllib.robotparser``       | :mod:`py2:robotparser`              | :mod:`py3:urllib.robotparser`         |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``urllib_robotparser``       | :mod:`py2:robotparser`              | :mod:`py3:urllib.robotparser`         |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``UserDict``                 | :class:`py2:UserDict.UserDict`      | :class:`py3:collections.UserDict`     |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``UserList``                 | :class:`py2:UserList.UserList`      | :class:`py3:collections.UserList`     |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``UserString``               | :class:`py2:UserString.UserString`  | :class:`py3:collections.UserString`   |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``winreg``                   | :mod:`py2:_winreg`                  | :mod:`py3:winreg`                     |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``xmlrpc_client``            | :mod:`py2:xmlrpclib`                | :mod:`py3:xmlrpc.client`              |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``xmlrpc_server``            | :mod:`py2:SimpleXMLRPCServer`       | :mod:`py3:xmlrpc.server`              |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``xrange``                   | :func:`py2:xrange`                  | :func:`py3:range`                     |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``zip``                      | :func:`py2:itertools.izip`          | :func:`py3:zip`                       |
++------------------------------+-------------------------------------+---------------------------------------+
+| ``zip_longest``              | :func:`py2:itertools.izip_longest`  | :func:`py3:itertools.zip_longest`     |
++------------------------------+-------------------------------------+---------------------------------------+
+
+urllib parse
+<<<<<<<<<<<<
+
+.. module:: six.moves.urllib.parse
+   :synopsis: Stuff from :mod:`py2:urlparse` and :mod:`py2:urllib` in Python 2 and :mod:`py3:urllib.parse` in Python 3
+
+Contains functions from Python 3's :mod:`py3:urllib.parse` and Python 2's:
+
+:mod:`py2:urlparse`:
+
+* :func:`py2:urlparse.ParseResult`
+* :func:`py2:urlparse.SplitResult`
+* :func:`py2:urlparse.urlparse`
+* :func:`py2:urlparse.urlunparse`
+* :func:`py2:urlparse.parse_qs`
+* :func:`py2:urlparse.parse_qsl`
+* :func:`py2:urlparse.urljoin`
+* :func:`py2:urlparse.urldefrag`
+* :func:`py2:urlparse.urlsplit`
+* :func:`py2:urlparse.urlunsplit`
+* :func:`py2:urlparse.splitquery`
+* :func:`py2:urlparse.uses_fragment`
+* :func:`py2:urlparse.uses_netloc`
+* :func:`py2:urlparse.uses_params`
+* :func:`py2:urlparse.uses_query`
+* :func:`py2:urlparse.uses_relative`
+
+and :mod:`py2:urllib`:
+
+* :func:`py2:urllib.quote`
+* :func:`py2:urllib.quote_plus`
+* :func:`py2:urllib.splittag`
+* :func:`py2:urllib.splituser`
+* :func:`py2:urllib.splitvalue`
+* :func:`py2:urllib.unquote` (also exposed as :func:`py3:urllib.parse.unquote_to_bytes`)
+* :func:`py2:urllib.unquote_plus`
+* :func:`py2:urllib.urlencode`
+
+
+urllib error
+<<<<<<<<<<<<
+
+.. module:: six.moves.urllib.error
+   :synopsis: Stuff from :mod:`py2:urllib` and :mod:`py2:urllib2` in Python 2 and :mod:`py3:urllib.error` in Python 3
+
+Contains exceptions from Python 3's :mod:`py3:urllib.error` and Python 2's:
+
+:mod:`py2:urllib`:
+
+* :exc:`py2:urllib.ContentTooShortError`
+
+and :mod:`py2:urllib2`:
+
+* :exc:`py2:urllib2.URLError`
+* :exc:`py2:urllib2.HTTPError`
+
+
+urllib request
+<<<<<<<<<<<<<<
+
+.. module:: six.moves.urllib.request
+   :synopsis: Stuff from :mod:`py2:urllib` and :mod:`py2:urllib2` in Python 2 and :mod:`py3:urllib.request` in Python 3
+
+Contains items from Python 3's :mod:`py3:urllib.request` and Python 2's:
+
+:mod:`py2:urllib`:
+
+* :func:`py2:urllib.pathname2url`
+* :func:`py2:urllib.url2pathname`
+* :func:`py2:urllib.getproxies`
+* :func:`py2:urllib.urlretrieve`
+* :func:`py2:urllib.urlcleanup`
+* :class:`py2:urllib.URLopener`
+* :class:`py2:urllib.FancyURLopener`
+* :func:`py2:urllib.proxy_bypass`
+
+and :mod:`py2:urllib2`:
+
+* :func:`py2:urllib2.urlopen`
+* :func:`py2:urllib2.install_opener`
+* :func:`py2:urllib2.build_opener`
+* :func:`py2:urllib2.parse_http_list`
+* :func:`py2:urllib2.parse_keqv_list`
+* :class:`py2:urllib2.Request`
+* :class:`py2:urllib2.OpenerDirector`
+* :class:`py2:urllib2.HTTPDefaultErrorHandler`
+* :class:`py2:urllib2.HTTPRedirectHandler`
+* :class:`py2:urllib2.HTTPCookieProcessor`
+* :class:`py2:urllib2.ProxyHandler`
+* :class:`py2:urllib2.BaseHandler`
+* :class:`py2:urllib2.HTTPPasswordMgr`
+* :class:`py2:urllib2.HTTPPasswordMgrWithDefaultRealm`
+* :class:`py2:urllib2.AbstractBasicAuthHandler`
+* :class:`py2:urllib2.HTTPBasicAuthHandler`
+* :class:`py2:urllib2.ProxyBasicAuthHandler`
+* :class:`py2:urllib2.AbstractDigestAuthHandler`
+* :class:`py2:urllib2.HTTPDigestAuthHandler`
+* :class:`py2:urllib2.ProxyDigestAuthHandler`
+* :class:`py2:urllib2.HTTPHandler`
+* :class:`py2:urllib2.HTTPSHandler`
+* :class:`py2:urllib2.FileHandler`
+* :class:`py2:urllib2.FTPHandler`
+* :class:`py2:urllib2.CacheFTPHandler`
+* :class:`py2:urllib2.UnknownHandler`
+* :class:`py2:urllib2.HTTPErrorProcessor`
+
+
+urllib response
+<<<<<<<<<<<<<<<
+
+.. module:: six.moves.urllib.response
+   :synopsis: Stuff from :mod:`py2:urllib` in Python 2 and :mod:`py3:urllib.response` in Python 3
+
+Contains classes from Python 3's :mod:`py3:urllib.response` and Python 2's:
+
+:mod:`py2:urllib`:
+
+* :class:`py2:urllib.addbase`
+* :class:`py2:urllib.addclosehook`
+* :class:`py2:urllib.addinfo`
+* :class:`py2:urllib.addinfourl`
+
+
+Advanced - Customizing renames
+<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
+
+.. currentmodule:: six
+
+It is possible to add additional names to the :mod:`six.moves` namespace.
+
+
+.. function:: add_move(item)
+
+   Add *item* to the :mod:`six.moves` mapping.  *item* should be a
+   :class:`MovedAttribute` or :class:`MovedModule` instance.
+
+
+.. function:: remove_move(name)
+
+   Remove the :mod:`six.moves` mapping called *name*.  *name* should be a
+   string.
+
+
+Instances of the following classes can be passed to :func:`add_move`.  Neither
+have any public members.
+
+
+.. class:: MovedModule(name, old_mod, new_mod)
+
+   Create a mapping for :mod:`six.moves` called *name* that references different
+   modules in Python 2 and 3.  *old_mod* is the name of the Python 2 module.
+   *new_mod* is the name of the Python 3 module.
+
+
+.. class:: MovedAttribute(name, old_mod, new_mod, old_attr=None, new_attr=None)
+
+   Create a mapping for :mod:`six.moves` called *name* that references different
+   attributes in Python 2 and 3.  *old_mod* is the name of the Python 2 module.
+   *new_mod* is the name of the Python 3 module.  If *new_attr* is not given, it
+   defaults to *old_attr*.  If neither is given, they both default to *name*.
diff --git a/third_party/python/six/setup.cfg b/third_party/python/six/setup.cfg
new file mode 100644
index 0000000000..fb1f5367a4
--- /dev/null
+++ b/third_party/python/six/setup.cfg
@@ -0,0 +1,24 @@
+[bdist_wheel]
+universal = 1
+
+[flake8]
+max-line-length = 100
+ignore = F821
+
+[metadata]
+license_file = LICENSE
+
+[tool:pytest]
+minversion = 2.2.0
+pep8ignore = 
+	documentation/*.py ALL
+	test_six.py ALL
+flakes-ignore = 
+	documentation/*.py ALL
+	test_six.py ALL
+	six.py UndefinedName
+
+[egg_info]
+tag_build = 
+tag_date = 0
+
diff --git a/third_party/python/six/setup.py b/third_party/python/six/setup.py
new file mode 100644
index 0000000000..97c685b5a5
--- /dev/null
+++ b/third_party/python/six/setup.py
@@ -0,0 +1,58 @@
+# Copyright (c) 2010-2019 Benjamin Peterson
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+from __future__ import with_statement
+
+# Six is a dependency of setuptools, so using setuptools creates a
+# circular dependency when building a Python stack from source. We
+# therefore allow falling back to distutils to install six.
+try:
+    from setuptools import setup
+except ImportError:
+    from distutils.core import setup
+
+import six
+
+six_classifiers = [
+    "Development Status :: 5 - Production/Stable",
+    "Programming Language :: Python :: 2",
+    "Programming Language :: Python :: 3",
+    "Intended Audience :: Developers",
+    "License :: OSI Approved :: MIT License",
+    "Topic :: Software Development :: Libraries",
+    "Topic :: Utilities",
+]
+
+with open("README.rst", "r") as fp:
+    six_long_description = fp.read()
+
+setup(name="six",
+      version=six.__version__,
+      author="Benjamin Peterson",
+      author_email="benjamin@python.org",
+      url="https://github.com/benjaminp/six",
+      tests_require=["pytest"],
+      py_modules=["six"],
+      description="Python 2 and 3 compatibility utilities",
+      long_description=six_long_description,
+      license="MIT",
+      classifiers=six_classifiers,
+      python_requires=">=2.6, !=3.0.*, !=3.1.*",
+      )
diff --git a/third_party/python/six/six.py b/third_party/python/six/six.py
new file mode 100644
index 0000000000..357e624abc
--- /dev/null
+++ b/third_party/python/six/six.py
@@ -0,0 +1,963 @@
+# Copyright (c) 2010-2019 Benjamin Peterson
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+"""Utilities for writing code that runs on Python 2 and 3"""
+
+from __future__ import absolute_import
+
+import functools
+import itertools
+import operator
+import sys
+import types
+
+__author__ = "Benjamin Peterson <benjamin@python.org>"
+__version__ = "1.13.0"
+
+
+# Useful for very coarse version differentiation.
+PY2 = sys.version_info[0] == 2
+PY3 = sys.version_info[0] == 3
+PY34 = sys.version_info[0:2] >= (3, 4)
+
+if PY3:
+    string_types = str,
+    integer_types = int,
+    class_types = type,
+    text_type = str
+    binary_type = bytes
+
+    MAXSIZE = sys.maxsize
+else:
+    string_types = basestring,
+    integer_types = (int, long)
+    class_types = (type, types.ClassType)
+    text_type = unicode
+    binary_type = str
+
+    if sys.platform.startswith("java"):
+        # Jython always uses 32 bits.
+        MAXSIZE = int((1 << 31) - 1)
+    else:
+        # It's possible to have sizeof(long) != sizeof(Py_ssize_t).
+        class X(object):
+
+            def __len__(self):
+                return 1 << 31
+        try:
+            len(X())
+        except OverflowError:
+            # 32-bit
+            MAXSIZE = int((1 << 31) - 1)
+        else:
+            # 64-bit
+            MAXSIZE = int((1 << 63) - 1)
+        del X
+
+
+def _add_doc(func, doc):
+    """Add documentation to a function."""
+    func.__doc__ = doc
+
+
+def _import_module(name):
+    """Import module, returning the module after the last dot."""
+    __import__(name)
+    return sys.modules[name]
+
+
+class _LazyDescr(object):
+
+    def __init__(self, name):
+        self.name = name
+
+    def __get__(self, obj, tp):
+        result = self._resolve()
+        setattr(obj, self.name, result)  # Invokes __set__.
+        try:
+            # This is a bit ugly, but it avoids running this again by
+            # removing this descriptor.
+            delattr(obj.__class__, self.name)
+        except AttributeError:
+            pass
+        return result
+
+
+class MovedModule(_LazyDescr):
+
+    def __init__(self, name, old, new=None):
+        super(MovedModule, self).__init__(name)
+        if PY3:
+            if new is None:
+                new = name
+            self.mod = new
+        else:
+            self.mod = old
+
+    def _resolve(self):
+        return _import_module(self.mod)
+
+    def __getattr__(self, attr):
+        _module = self._resolve()
+        value = getattr(_module, attr)
+        setattr(self, attr, value)
+        return value
+
+
+class _LazyModule(types.ModuleType):
+
+    def __init__(self, name):
+        super(_LazyModule, self).__init__(name)
+        self.__doc__ = self.__class__.__doc__
+
+    def __dir__(self):
+        attrs = ["__doc__", "__name__"]
+        attrs += [attr.name for attr in self._moved_attributes]
+        return attrs
+
+    # Subclasses should override this
+    _moved_attributes = []
+
+
+class MovedAttribute(_LazyDescr):
+
+    def __init__(self, name, old_mod, new_mod, old_attr=None, new_attr=None):
+        super(MovedAttribute, self).__init__(name)
+        if PY3:
+            if new_mod is None:
+                new_mod = name
+            self.mod = new_mod
+            if new_attr is None:
+                if old_attr is None:
+                    new_attr = name
+                else:
+                    new_attr = old_attr
+            self.attr = new_attr
+        else:
+            self.mod = old_mod
+            if old_attr is None:
+                old_attr = name
+            self.attr = old_attr
+
+    def _resolve(self):
+        module = _import_module(self.mod)
+        return getattr(module, self.attr)
+
+
+class _SixMetaPathImporter(object):
+
+    """
+    A meta path importer to import six.moves and its submodules.
+
+    This class implements a PEP302 finder and loader. It should be compatible
+    with Python 2.5 and all existing versions of Python3
+    """
+
+    def __init__(self, six_module_name):
+        self.name = six_module_name
+        self.known_modules = {}
+
+    def _add_module(self, mod, *fullnames):
+        for fullname in fullnames:
+            self.known_modules[self.name + "." + fullname] = mod
+
+    def _get_module(self, fullname):
+        return self.known_modules[self.name + "." + fullname]
+
+    def find_module(self, fullname, path=None):
+        if fullname in self.known_modules:
+            return self
+        return None
+
+    def __get_module(self, fullname):
+        try:
+            return self.known_modules[fullname]
+        except KeyError:
+            raise ImportError("This loader does not know module " + fullname)
+
+    def load_module(self, fullname):
+        try:
+            # in case of a reload
+            return sys.modules[fullname]
+        except KeyError:
+            pass
+        mod = self.__get_module(fullname)
+        if isinstance(mod, MovedModule):
+            mod = mod._resolve()
+        else:
+            mod.__loader__ = self
+        sys.modules[fullname] = mod
+        return mod
+
+    def is_package(self, fullname):
+        """
+        Return true, if the named module is a package.
+
+        We need this method to get correct spec objects with
+        Python 3.4 (see PEP451)
+        """
+        return hasattr(self.__get_module(fullname), "__path__")
+
+    def get_code(self, fullname):
+        """Return None
+
+        Required, if is_package is implemented"""
+        self.__get_module(fullname)  # eventually raises ImportError
+        return None
+    get_source = get_code  # same as get_code
+
+_importer = _SixMetaPathImporter(__name__)
+
+
+class _MovedItems(_LazyModule):
+
+    """Lazy loading of moved objects"""
+    __path__ = []  # mark as package
+
+
+_moved_attributes = [
+    MovedAttribute("cStringIO", "cStringIO", "io", "StringIO"),
+    MovedAttribute("filter", "itertools", "builtins", "ifilter", "filter"),
+    MovedAttribute("filterfalse", "itertools", "itertools", "ifilterfalse", "filterfalse"),
+    MovedAttribute("input", "__builtin__", "builtins", "raw_input", "input"),
+    MovedAttribute("intern", "__builtin__", "sys"),
+    MovedAttribute("map", "itertools", "builtins", "imap", "map"),
+    MovedAttribute("getcwd", "os", "os", "getcwdu", "getcwd"),
+    MovedAttribute("getcwdb", "os", "os", "getcwd", "getcwdb"),
+    MovedAttribute("getoutput", "commands", "subprocess"),
+    MovedAttribute("range", "__builtin__", "builtins", "xrange", "range"),
+    MovedAttribute("reload_module", "__builtin__", "importlib" if PY34 else "imp", "reload"),
+    MovedAttribute("reduce", "__builtin__", "functools"),
+    MovedAttribute("shlex_quote", "pipes", "shlex", "quote"),
+    MovedAttribute("StringIO", "StringIO", "io"),
+    MovedAttribute("UserDict", "UserDict", "collections"),
+    MovedAttribute("UserList", "UserList", "collections"),
+    MovedAttribute("UserString", "UserString", "collections"),
+    MovedAttribute("xrange", "__builtin__", "builtins", "xrange", "range"),
+    MovedAttribute("zip", "itertools", "builtins", "izip", "zip"),
+    MovedAttribute("zip_longest", "itertools", "itertools", "izip_longest", "zip_longest"),
+    MovedModule("builtins", "__builtin__"),
+    MovedModule("configparser", "ConfigParser"),
+    MovedModule("collections_abc", "collections", "collections.abc" if sys.version_info >= (3, 3) else "collections"),
+    MovedModule("copyreg", "copy_reg"),
+    MovedModule("dbm_gnu", "gdbm", "dbm.gnu"),
+    MovedModule("dbm_ndbm", "dbm", "dbm.ndbm"),
+    MovedModule("_dummy_thread", "dummy_thread", "_dummy_thread"),
+    MovedModule("http_cookiejar", "cookielib", "http.cookiejar"),
+    MovedModule("http_cookies", "Cookie", "http.cookies"),
+    MovedModule("html_entities", "htmlentitydefs", "html.entities"),
+    MovedModule("html_parser", "HTMLParser", "html.parser"),
+    MovedModule("http_client", "httplib", "http.client"),
+    MovedModule("email_mime_base", "email.MIMEBase", "email.mime.base"),
+    MovedModule("email_mime_image", "email.MIMEImage", "email.mime.image"),
+    MovedModule("email_mime_multipart", "email.MIMEMultipart", "email.mime.multipart"),
+    MovedModule("email_mime_nonmultipart", "email.MIMENonMultipart", "email.mime.nonmultipart"),
+    MovedModule("email_mime_text", "email.MIMEText", "email.mime.text"),
+    MovedModule("BaseHTTPServer", "BaseHTTPServer", "http.server"),
+    MovedModule("CGIHTTPServer", "CGIHTTPServer", "http.server"),
+    MovedModule("SimpleHTTPServer", "SimpleHTTPServer", "http.server"),
+    MovedModule("cPickle", "cPickle", "pickle"),
+    MovedModule("queue", "Queue"),
+    MovedModule("reprlib", "repr"),
+    MovedModule("socketserver", "SocketServer"),
+    MovedModule("_thread", "thread", "_thread"),
+    MovedModule("tkinter", "Tkinter"),
+    MovedModule("tkinter_dialog", "Dialog", "tkinter.dialog"),
+    MovedModule("tkinter_filedialog", "FileDialog", "tkinter.filedialog"),
+    MovedModule("tkinter_scrolledtext", "ScrolledText", "tkinter.scrolledtext"),
+    MovedModule("tkinter_simpledialog", "SimpleDialog", "tkinter.simpledialog"),
+    MovedModule("tkinter_tix", "Tix", "tkinter.tix"),
+    MovedModule("tkinter_ttk", "ttk", "tkinter.ttk"),
+    MovedModule("tkinter_constants", "Tkconstants", "tkinter.constants"),
+    MovedModule("tkinter_dnd", "Tkdnd", "tkinter.dnd"),
+    MovedModule("tkinter_colorchooser", "tkColorChooser",
+                "tkinter.colorchooser"),
+    MovedModule("tkinter_commondialog", "tkCommonDialog",
+                "tkinter.commondialog"),
+    MovedModule("tkinter_tkfiledialog", "tkFileDialog", "tkinter.filedialog"),
+    MovedModule("tkinter_font", "tkFont", "tkinter.font"),
+    MovedModule("tkinter_messagebox", "tkMessageBox", "tkinter.messagebox"),
+    MovedModule("tkinter_tksimpledialog", "tkSimpleDialog",
+                "tkinter.simpledialog"),
+    MovedModule("urllib_parse", __name__ + ".moves.urllib_parse", "urllib.parse"),
+    MovedModule("urllib_error", __name__ + ".moves.urllib_error", "urllib.error"),
+    MovedModule("urllib", __name__ + ".moves.urllib", __name__ + ".moves.urllib"),
+    MovedModule("urllib_robotparser", "robotparser", "urllib.robotparser"),
+    MovedModule("xmlrpc_client", "xmlrpclib", "xmlrpc.client"),
+    MovedModule("xmlrpc_server", "SimpleXMLRPCServer", "xmlrpc.server"),
+]
+# Add windows specific modules.
+if sys.platform == "win32":
+    _moved_attributes += [
+        MovedModule("winreg", "_winreg"),
+    ]
+
+for attr in _moved_attributes:
+    setattr(_MovedItems, attr.name, attr)
+    if isinstance(attr, MovedModule):
+        _importer._add_module(attr, "moves." + attr.name)
+del attr
+
+_MovedItems._moved_attributes = _moved_attributes
+
+moves = _MovedItems(__name__ + ".moves")
+_importer._add_module(moves, "moves")
+
+
+class Module_six_moves_urllib_parse(_LazyModule):
+
+    """Lazy loading of moved objects in six.moves.urllib_parse"""
+
+
+_urllib_parse_moved_attributes = [
+    MovedAttribute("ParseResult", "urlparse", "urllib.parse"),
+    MovedAttribute("SplitResult", "urlparse", "urllib.parse"),
+    MovedAttribute("parse_qs", "urlparse", "urllib.parse"),
+    MovedAttribute("parse_qsl", "urlparse", "urllib.parse"),
+    MovedAttribute("urldefrag", "urlparse", "urllib.parse"),
+    MovedAttribute("urljoin", "urlparse", "urllib.parse"),
+    MovedAttribute("urlparse", "urlparse", "urllib.parse"),
+    MovedAttribute("urlsplit", "urlparse", "urllib.parse"),
+    MovedAttribute("urlunparse", "urlparse", "urllib.parse"),
+    MovedAttribute("urlunsplit", "urlparse", "urllib.parse"),
+    MovedAttribute("quote", "urllib", "urllib.parse"),
+    MovedAttribute("quote_plus", "urllib", "urllib.parse"),
+    MovedAttribute("unquote", "urllib", "urllib.parse"),
+    MovedAttribute("unquote_plus", "urllib", "urllib.parse"),
+    MovedAttribute("unquote_to_bytes", "urllib", "urllib.parse", "unquote", "unquote_to_bytes"),
+    MovedAttribute("urlencode", "urllib", "urllib.parse"),
+    MovedAttribute("splitquery", "urllib", "urllib.parse"),
+    MovedAttribute("splittag", "urllib", "urllib.parse"),
+    MovedAttribute("splituser", "urllib", "urllib.parse"),
+    MovedAttribute("splitvalue", "urllib", "urllib.parse"),
+    MovedAttribute("uses_fragment", "urlparse", "urllib.parse"),
+    MovedAttribute("uses_netloc", "urlparse", "urllib.parse"),
+    MovedAttribute("uses_params", "urlparse", "urllib.parse"),
+    MovedAttribute("uses_query", "urlparse", "urllib.parse"),
+    MovedAttribute("uses_relative", "urlparse", "urllib.parse"),
+]
+for attr in _urllib_parse_moved_attributes:
+    setattr(Module_six_moves_urllib_parse, attr.name, attr)
+del attr
+
+Module_six_moves_urllib_parse._moved_attributes = _urllib_parse_moved_attributes
+
+_importer._add_module(Module_six_moves_urllib_parse(__name__ + ".moves.urllib_parse"),
+                      "moves.urllib_parse", "moves.urllib.parse")
+
+
+class Module_six_moves_urllib_error(_LazyModule):
+
+    """Lazy loading of moved objects in six.moves.urllib_error"""
+
+
+_urllib_error_moved_attributes = [
+    MovedAttribute("URLError", "urllib2", "urllib.error"),
+    MovedAttribute("HTTPError", "urllib2", "urllib.error"),
+    MovedAttribute("ContentTooShortError", "urllib", "urllib.error"),
+]
+for attr in _urllib_error_moved_attributes:
+    setattr(Module_six_moves_urllib_error, attr.name, attr)
+del attr
+
+Module_six_moves_urllib_error._moved_attributes = _urllib_error_moved_attributes
+
+_importer._add_module(Module_six_moves_urllib_error(__name__ + ".moves.urllib.error"),
+                      "moves.urllib_error", "moves.urllib.error")
+
+
+class Module_six_moves_urllib_request(_LazyModule):
+
+    """Lazy loading of moved objects in six.moves.urllib_request"""
+
+
+_urllib_request_moved_attributes = [
+    MovedAttribute("urlopen", "urllib2", "urllib.request"),
+    MovedAttribute("install_opener", "urllib2", "urllib.request"),
+    MovedAttribute("build_opener", "urllib2", "urllib.request"),
+    MovedAttribute("pathname2url", "urllib", "urllib.request"),
+    MovedAttribute("url2pathname", "urllib", "urllib.request"),
+    MovedAttribute("getproxies", "urllib", "urllib.request"),
+    MovedAttribute("Request", "urllib2", "urllib.request"),
+    MovedAttribute("OpenerDirector", "urllib2", "urllib.request"),
+    MovedAttribute("HTTPDefaultErrorHandler", "urllib2", "urllib.request"),
+    MovedAttribute("HTTPRedirectHandler", "urllib2", "urllib.request"),
+    MovedAttribute("HTTPCookieProcessor", "urllib2", "urllib.request"),
+    MovedAttribute("ProxyHandler", "urllib2", "urllib.request"),
+    MovedAttribute("BaseHandler", "urllib2", "urllib.request"),
+    MovedAttribute("HTTPPasswordMgr", "urllib2", "urllib.request"),
+    MovedAttribute("HTTPPasswordMgrWithDefaultRealm", "urllib2", "urllib.request"),
+    MovedAttribute("AbstractBasicAuthHandler", "urllib2", "urllib.request"),
+    MovedAttribute("HTTPBasicAuthHandler", "urllib2", "urllib.request"),
+    MovedAttribute("ProxyBasicAuthHandler", "urllib2", "urllib.request"),
+    MovedAttribute("AbstractDigestAuthHandler", "urllib2", "urllib.request"),
+    MovedAttribute("HTTPDigestAuthHandler", "urllib2", "urllib.request"),
+    MovedAttribute("ProxyDigestAuthHandler", "urllib2", "urllib.request"),
+    MovedAttribute("HTTPHandler", "urllib2", "urllib.request"),
+    MovedAttribute("HTTPSHandler", "urllib2", "urllib.request"),
+    MovedAttribute("FileHandler", "urllib2", "urllib.request"),
+    MovedAttribute("FTPHandler", "urllib2", "urllib.request"),
+    MovedAttribute("CacheFTPHandler", "urllib2", "urllib.request"),
+    MovedAttribute("UnknownHandler", "urllib2", "urllib.request"),
+    MovedAttribute("HTTPErrorProcessor", "urllib2", "urllib.request"),
+    MovedAttribute("urlretrieve", "urllib", "urllib.request"),
+    MovedAttribute("urlcleanup", "urllib", "urllib.request"),
+    MovedAttribute("URLopener", "urllib", "urllib.request"),
+    MovedAttribute("FancyURLopener", "urllib", "urllib.request"),
+    MovedAttribute("proxy_bypass", "urllib", "urllib.request"),
+    MovedAttribute("parse_http_list", "urllib2", "urllib.request"),
+    MovedAttribute("parse_keqv_list", "urllib2", "urllib.request"),
+]
+for attr in _urllib_request_moved_attributes:
+    setattr(Module_six_moves_urllib_request, attr.name, attr)
+del attr
+
+Module_six_moves_urllib_request._moved_attributes = _urllib_request_moved_attributes
+
+_importer._add_module(Module_six_moves_urllib_request(__name__ + ".moves.urllib.request"),
+                      "moves.urllib_request", "moves.urllib.request")
+
+
+class Module_six_moves_urllib_response(_LazyModule):
+
+    """Lazy loading of moved objects in six.moves.urllib_response"""
+
+
+_urllib_response_moved_attributes = [
+    MovedAttribute("addbase", "urllib", "urllib.response"),
+    MovedAttribute("addclosehook", "urllib", "urllib.response"),
+    MovedAttribute("addinfo", "urllib", "urllib.response"),
+    MovedAttribute("addinfourl", "urllib", "urllib.response"),
+]
+for attr in _urllib_response_moved_attributes:
+    setattr(Module_six_moves_urllib_response, attr.name, attr)
+del attr
+
+Module_six_moves_urllib_response._moved_attributes = _urllib_response_moved_attributes
+
+_importer._add_module(Module_six_moves_urllib_response(__name__ + ".moves.urllib.response"),
+                      "moves.urllib_response", "moves.urllib.response")
+
+
+class Module_six_moves_urllib_robotparser(_LazyModule):
+
+    """Lazy loading of moved objects in six.moves.urllib_robotparser"""
+
+
+_urllib_robotparser_moved_attributes = [
+    MovedAttribute("RobotFileParser", "robotparser", "urllib.robotparser"),
+]
+for attr in _urllib_robotparser_moved_attributes:
+    setattr(Module_six_moves_urllib_robotparser, attr.name, attr)
+del attr
+
+Module_six_moves_urllib_robotparser._moved_attributes = _urllib_robotparser_moved_attributes
+
+_importer._add_module(Module_six_moves_urllib_robotparser(__name__ + ".moves.urllib.robotparser"),
+                      "moves.urllib_robotparser", "moves.urllib.robotparser")
+
+
+class Module_six_moves_urllib(types.ModuleType):
+
+    """Create a six.moves.urllib namespace that resembles the Python 3 namespace"""
+    __path__ = []  # mark as package
+    parse = _importer._get_module("moves.urllib_parse")
+    error = _importer._get_module("moves.urllib_error")
+    request = _importer._get_module("moves.urllib_request")
+    response = _importer._get_module("moves.urllib_response")
+    robotparser = _importer._get_module("moves.urllib_robotparser")
+
+    def __dir__(self):
+        return ['parse', 'error', 'request', 'response', 'robotparser']
+
+_importer._add_module(Module_six_moves_urllib(__name__ + ".moves.urllib"),
+                      "moves.urllib")
+
+
+def add_move(move):
+    """Add an item to six.moves."""
+    setattr(_MovedItems, move.name, move)
+
+
+def remove_move(name):
+    """Remove item from six.moves."""
+    try:
+        delattr(_MovedItems, name)
+    except AttributeError:
+        try:
+            del moves.__dict__[name]
+        except KeyError:
+            raise AttributeError("no such move, %r" % (name,))
+
+
+if PY3:
+    _meth_func = "__func__"
+    _meth_self = "__self__"
+
+    _func_closure = "__closure__"
+    _func_code = "__code__"
+    _func_defaults = "__defaults__"
+    _func_globals = "__globals__"
+else:
+    _meth_func = "im_func"
+    _meth_self = "im_self"
+
+    _func_closure = "func_closure"
+    _func_code = "func_code"
+    _func_defaults = "func_defaults"
+    _func_globals = "func_globals"
+
+
+try:
+    advance_iterator = next
+except NameError:
+    def advance_iterator(it):
+        return it.next()
+next = advance_iterator
+
+
+try:
+    callable = callable
+except NameError:
+    def callable(obj):
+        return any("__call__" in klass.__dict__ for klass in type(obj).__mro__)
+
+
+if PY3:
+    def get_unbound_function(unbound):
+        return unbound
+
+    create_bound_method = types.MethodType
+
+    def create_unbound_method(func, cls):
+        return func
+
+    Iterator = object
+else:
+    def get_unbound_function(unbound):
+        return unbound.im_func
+
+    def create_bound_method(func, obj):
+        return types.MethodType(func, obj, obj.__class__)
+
+    def create_unbound_method(func, cls):
+        return types.MethodType(func, None, cls)
+
+    class Iterator(object):
+
+        def next(self):
+            return type(self).__next__(self)
+
+    callable = callable
+_add_doc(get_unbound_function,
+         """Get the function out of a possibly unbound function""")
+
+
+get_method_function = operator.attrgetter(_meth_func)
+get_method_self = operator.attrgetter(_meth_self)
+get_function_closure = operator.attrgetter(_func_closure)
+get_function_code = operator.attrgetter(_func_code)
+get_function_defaults = operator.attrgetter(_func_defaults)
+get_function_globals = operator.attrgetter(_func_globals)
+
+
+if PY3:
+    def iterkeys(d, **kw):
+        return iter(d.keys(**kw))
+
+    def itervalues(d, **kw):
+        return iter(d.values(**kw))
+
+    def iteritems(d, **kw):
+        return iter(d.items(**kw))
+
+    def iterlists(d, **kw):
+        return iter(d.lists(**kw))
+
+    viewkeys = operator.methodcaller("keys")
+
+    viewvalues = operator.methodcaller("values")
+
+    viewitems = operator.methodcaller("items")
+else:
+    def iterkeys(d, **kw):
+        return d.iterkeys(**kw)
+
+    def itervalues(d, **kw):
+        return d.itervalues(**kw)
+
+    def iteritems(d, **kw):
+        return d.iteritems(**kw)
+
+    def iterlists(d, **kw):
+        return d.iterlists(**kw)
+
+    viewkeys = operator.methodcaller("viewkeys")
+
+    viewvalues = operator.methodcaller("viewvalues")
+
+    viewitems = operator.methodcaller("viewitems")
+
+_add_doc(iterkeys, "Return an iterator over the keys of a dictionary.")
+_add_doc(itervalues, "Return an iterator over the values of a dictionary.")
+_add_doc(iteritems,
+         "Return an iterator over the (key, value) pairs of a dictionary.")
+_add_doc(iterlists,
+         "Return an iterator over the (key, [values]) pairs of a dictionary.")
+
+
+if PY3:
+    def b(s):
+        return s.encode("latin-1")
+
+    def u(s):
+        return s
+    unichr = chr
+    import struct
+    int2byte = struct.Struct(">B").pack
+    del struct
+    byte2int = operator.itemgetter(0)
+    indexbytes = operator.getitem
+    iterbytes = iter
+    import io
+    StringIO = io.StringIO
+    BytesIO = io.BytesIO
+    del io
+    _assertCountEqual = "assertCountEqual"
+    if sys.version_info[1] <= 1:
+        _assertRaisesRegex = "assertRaisesRegexp"
+        _assertRegex = "assertRegexpMatches"
+    else:
+        _assertRaisesRegex = "assertRaisesRegex"
+        _assertRegex = "assertRegex"
+else:
+    def b(s):
+        return s
+    # Workaround for standalone backslash
+
+    def u(s):
+        return unicode(s.replace(r'\\', r'\\\\'), "unicode_escape")
+    unichr = unichr
+    int2byte = chr
+
+    def byte2int(bs):
+        return ord(bs[0])
+
+    def indexbytes(buf, i):
+        return ord(buf[i])
+    iterbytes = functools.partial(itertools.imap, ord)
+    import StringIO
+    StringIO = BytesIO = StringIO.StringIO
+    _assertCountEqual = "assertItemsEqual"
+    _assertRaisesRegex = "assertRaisesRegexp"
+    _assertRegex = "assertRegexpMatches"
+_add_doc(b, """Byte literal""")
+_add_doc(u, """Text literal""")
+
+
+def assertCountEqual(self, *args, **kwargs):
+    return getattr(self, _assertCountEqual)(*args, **kwargs)
+
+
+def assertRaisesRegex(self, *args, **kwargs):
+    return getattr(self, _assertRaisesRegex)(*args, **kwargs)
+
+
+def assertRegex(self, *args, **kwargs):
+    return getattr(self, _assertRegex)(*args, **kwargs)
+
+
+if PY3:
+    exec_ = getattr(moves.builtins, "exec")
+
+    def reraise(tp, value, tb=None):
+        try:
+            if value is None:
+                value = tp()
+            if value.__traceback__ is not tb:
+                raise value.with_traceback(tb)
+            raise value
+        finally:
+            value = None
+            tb = None
+
+else:
+    def exec_(_code_, _globs_=None, _locs_=None):
+        """Execute code in a namespace."""
+        if _globs_ is None:
+            frame = sys._getframe(1)
+            _globs_ = frame.f_globals
+            if _locs_ is None:
+                _locs_ = frame.f_locals
+            del frame
+        elif _locs_ is None:
+            _locs_ = _globs_
+        exec("""exec _code_ in _globs_, _locs_""")
+
+    exec_("""def reraise(tp, value, tb=None):
+    try:
+        raise tp, value, tb
+    finally:
+        tb = None
+""")
+
+
+if sys.version_info[:2] == (3, 2):
+    exec_("""def raise_from(value, from_value):
+    try:
+        if from_value is None:
+            raise value
+        raise value from from_value
+    finally:
+        value = None
+""")
+elif sys.version_info[:2] > (3, 2):
+    exec_("""def raise_from(value, from_value):
+    try:
+        raise value from from_value
+    finally:
+        value = None
+""")
+else:
+    def raise_from(value, from_value):
+        raise value
+
+
+print_ = getattr(moves.builtins, "print", None)
+if print_ is None:
+    def print_(*args, **kwargs):
+        """The new-style print function for Python 2.4 and 2.5."""
+        fp = kwargs.pop("file", sys.stdout)
+        if fp is None:
+            return
+
+        def write(data):
+            if not isinstance(data, basestring):
+                data = str(data)
+            # If the file has an encoding, encode unicode with it.
+            if (isinstance(fp, file) and
+                    isinstance(data, unicode) and
+                    fp.encoding is not None):
+                errors = getattr(fp, "errors", None)
+                if errors is None:
+                    errors = "strict"
+                data = data.encode(fp.encoding, errors)
+            fp.write(data)
+        want_unicode = False
+        sep = kwargs.pop("sep", None)
+        if sep is not None:
+            if isinstance(sep, unicode):
+                want_unicode = True
+            elif not isinstance(sep, str):
+                raise TypeError("sep must be None or a string")
+        end = kwargs.pop("end", None)
+        if end is not None:
+            if isinstance(end, unicode):
+                want_unicode = True
+            elif not isinstance(end, str):
+                raise TypeError("end must be None or a string")
+        if kwargs:
+            raise TypeError("invalid keyword arguments to print()")
+        if not want_unicode:
+            for arg in args:
+                if isinstance(arg, unicode):
+                    want_unicode = True
+                    break
+        if want_unicode:
+            newline = unicode("\n")
+            space = unicode(" ")
+        else:
+            newline = "\n"
+            space = " "
+        if sep is None:
+            sep = space
+        if end is None:
+            end = newline
+        for i, arg in enumerate(args):
+            if i:
+                write(sep)
+            write(arg)
+        write(end)
+if sys.version_info[:2] < (3, 3):
+    _print = print_
+
+    def print_(*args, **kwargs):
+        fp = kwargs.get("file", sys.stdout)
+        flush = kwargs.pop("flush", False)
+        _print(*args, **kwargs)
+        if flush and fp is not None:
+            fp.flush()
+
+_add_doc(reraise, """Reraise an exception.""")
+
+if sys.version_info[0:2] < (3, 4):
+    def wraps(wrapped, assigned=functools.WRAPPER_ASSIGNMENTS,
+              updated=functools.WRAPPER_UPDATES):
+        def wrapper(f):
+            f = functools.wraps(wrapped, assigned, updated)(f)
+            f.__wrapped__ = wrapped
+            return f
+        return wrapper
+else:
+    wraps = functools.wraps
+
+
+def with_metaclass(meta, *bases):
+    """Create a base class with a metaclass."""
+    # This requires a bit of explanation: the basic idea is to make a dummy
+    # metaclass for one level of class instantiation that replaces itself with
+    # the actual metaclass.
+    class metaclass(type):
+
+        def __new__(cls, name, this_bases, d):
+            if sys.version_info[:2] >= (3, 7):
+                # This version introduced PEP 560 that requires a bit
+                # of extra care (we mimic what is done by __build_class__).
+                resolved_bases = types.resolve_bases(bases)
+                if resolved_bases is not bases:
+                    d['__orig_bases__'] = bases
+            else:
+                resolved_bases = bases
+            return meta(name, resolved_bases, d)
+
+        @classmethod
+        def __prepare__(cls, name, this_bases):
+            return meta.__prepare__(name, bases)
+    return type.__new__(metaclass, 'temporary_class', (), {})
+
+
+def add_metaclass(metaclass):
+    """Class decorator for creating a class with a metaclass."""
+    def wrapper(cls):
+        orig_vars = cls.__dict__.copy()
+        slots = orig_vars.get('__slots__')
+        if slots is not None:
+            if isinstance(slots, str):
+                slots = [slots]
+            for slots_var in slots:
+                orig_vars.pop(slots_var)
+        orig_vars.pop('__dict__', None)
+        orig_vars.pop('__weakref__', None)
+        if hasattr(cls, '__qualname__'):
+            orig_vars['__qualname__'] = cls.__qualname__
+        return metaclass(cls.__name__, cls.__bases__, orig_vars)
+    return wrapper
+
+
+def ensure_binary(s, encoding='utf-8', errors='strict'):
+    """Coerce **s** to six.binary_type.
+
+    For Python 2:
+      - `unicode` -> encoded to `str`
+      - `str` -> `str`
+
+    For Python 3:
+      - `str` -> encoded to `bytes`
+      - `bytes` -> `bytes`
+    """
+    if isinstance(s, text_type):
+        return s.encode(encoding, errors)
+    elif isinstance(s, binary_type):
+        return s
+    else:
+        raise TypeError("not expecting type '%s'" % type(s))
+
+
+def ensure_str(s, encoding='utf-8', errors='strict'):
+    """Coerce *s* to `str`.
+
+    For Python 2:
+      - `unicode` -> encoded to `str`
+      - `str` -> `str`
+
+    For Python 3:
+      - `str` -> `str`
+      - `bytes` -> decoded to `str`
+    """
+    if not isinstance(s, (text_type, binary_type)):
+        raise TypeError("not expecting type '%s'" % type(s))
+    if PY2 and isinstance(s, text_type):
+        s = s.encode(encoding, errors)
+    elif PY3 and isinstance(s, binary_type):
+        s = s.decode(encoding, errors)
+    return s
+
+
+def ensure_text(s, encoding='utf-8', errors='strict'):
+    """Coerce *s* to six.text_type.
+
+    For Python 2:
+      - `unicode` -> `unicode`
+      - `str` -> `unicode`
+
+    For Python 3:
+      - `str` -> `str`
+      - `bytes` -> decoded to `str`
+    """
+    if isinstance(s, binary_type):
+        return s.decode(encoding, errors)
+    elif isinstance(s, text_type):
+        return s
+    else:
+        raise TypeError("not expecting type '%s'" % type(s))
+
+
+
+def python_2_unicode_compatible(klass):
+    """
+    A decorator that defines __unicode__ and __str__ methods under Python 2.
+    Under Python 3 it does nothing.
+
+    To support Python 2 and 3 with a single code base, define a __str__ method
+    returning text and apply this decorator to the class.
+    """
+    if PY2:
+        if '__str__' not in klass.__dict__:
+            raise ValueError("@python_2_unicode_compatible cannot be applied "
+                             "to %s because it doesn't define __str__()." %
+                             klass.__name__)
+        klass.__unicode__ = klass.__str__
+        klass.__str__ = lambda self: self.__unicode__().encode('utf-8')
+    return klass
+
+
+# Complete the moves implementation.
+# This code is at the end of this module to speed up module loading.
+# Turn this module into a package.
+__path__ = []  # required for PEP 302 and PEP 451
+__package__ = __name__  # see PEP 366 @ReservedAssignment
+if globals().get("__spec__") is not None:
+    __spec__.submodule_search_locations = []  # PEP 451 @UndefinedVariable
+# Remove other six meta path importers, since they cause problems. This can
+# happen if six is removed from sys.modules and then reloaded. (Setuptools does
+# this for some reason.)
+if sys.meta_path:
+    for i, importer in enumerate(sys.meta_path):
+        # Here's some real nastiness: Another "instance" of the six module might
+        # be floating around. Therefore, we can't use isinstance() to check for
+        # the six meta path importer, since the other six instance will have
+        # inserted an importer with different class.
+        if (type(importer).__name__ == "_SixMetaPathImporter" and
+                importer.name == __name__):
+            del sys.meta_path[i]
+            break
+    del i, importer
+# Finally, add the importer to the meta path import hook.
+sys.meta_path.append(_importer)
diff --git a/third_party/python/six/test_six.py b/third_party/python/six/test_six.py
new file mode 100644
index 0000000000..0b72067416
--- /dev/null
+++ b/third_party/python/six/test_six.py
@@ -0,0 +1,1060 @@
+# Copyright (c) 2010-2019 Benjamin Peterson
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+import operator
+import sys
+import types
+import unittest
+import abc
+
+import pytest
+
+import six
+
+
+def test_add_doc():
+    def f():
+        """Icky doc"""
+        pass
+    six._add_doc(f, """New doc""")
+    assert f.__doc__ == "New doc"
+
+
+def test_import_module():
+    from logging import handlers
+    m = six._import_module("logging.handlers")
+    assert m is handlers
+
+
+def test_integer_types():
+    assert isinstance(1, six.integer_types)
+    assert isinstance(-1, six.integer_types)
+    assert isinstance(six.MAXSIZE + 23, six.integer_types)
+    assert not isinstance(.1, six.integer_types)
+
+
+def test_string_types():
+    assert isinstance("hi", six.string_types)
+    assert isinstance(six.u("hi"), six.string_types)
+    assert issubclass(six.text_type, six.string_types)
+
+
+def test_class_types():
+    class X:
+        pass
+    class Y(object):
+        pass
+    assert isinstance(X, six.class_types)
+    assert isinstance(Y, six.class_types)
+    assert not isinstance(X(), six.class_types)
+
+
+def test_text_type():
+    assert type(six.u("hi")) is six.text_type
+
+
+def test_binary_type():
+    assert type(six.b("hi")) is six.binary_type
+
+
+def test_MAXSIZE():
+    try:
+        # This shouldn't raise an overflow error.
+        six.MAXSIZE.__index__()
+    except AttributeError:
+        # Before Python 2.6.
+        pass
+    pytest.raises(
+        (ValueError, OverflowError),
+        operator.mul, [None], six.MAXSIZE + 1)
+
+
+def test_lazy():
+    if six.PY3:
+        html_name = "html.parser"
+    else:
+        html_name = "HTMLParser"
+    assert html_name not in sys.modules
+    mod = six.moves.html_parser
+    assert sys.modules[html_name] is mod
+    assert "htmlparser" not in six._MovedItems.__dict__
+
+
+try:
+    import _tkinter
+except ImportError:
+    have_tkinter = False
+else:
+    have_tkinter = True
+
+have_gdbm = True
+try:
+    import gdbm
+except ImportError:
+    try:
+        import dbm.gnu
+    except ImportError:
+        have_gdbm = False
+
+@pytest.mark.parametrize("item_name",
+                          [item.name for item in six._moved_attributes])
+def test_move_items(item_name):
+    """Ensure that everything loads correctly."""
+    try:
+        item = getattr(six.moves, item_name)
+        if isinstance(item, types.ModuleType):
+            __import__("six.moves." + item_name)
+    except AttributeError:
+        if item_name == "zip_longest" and sys.version_info < (2, 6):
+            pytest.skip("zip_longest only available on 2.6+")
+    except ImportError:
+        if item_name == "winreg" and not sys.platform.startswith("win"):
+            pytest.skip("Windows only module")
+        if item_name.startswith("tkinter"):
+            if not have_tkinter:
+                pytest.skip("requires tkinter")
+            if item_name == "tkinter_ttk" and sys.version_info[:2] <= (2, 6):
+                pytest.skip("ttk only available on 2.7+")
+        if item_name.startswith("dbm_gnu") and not have_gdbm:
+            pytest.skip("requires gdbm")
+        raise
+    if sys.version_info[:2] >= (2, 6):
+        assert item_name in dir(six.moves)
+
+
+@pytest.mark.parametrize("item_name",
+                          [item.name for item in six._urllib_parse_moved_attributes])
+def test_move_items_urllib_parse(item_name):
+    """Ensure that everything loads correctly."""
+    if item_name == "ParseResult" and sys.version_info < (2, 5):
+        pytest.skip("ParseResult is only found on 2.5+")
+    if item_name in ("parse_qs", "parse_qsl") and sys.version_info < (2, 6):
+        pytest.skip("parse_qs[l] is new in 2.6")
+    if sys.version_info[:2] >= (2, 6):
+        assert item_name in dir(six.moves.urllib.parse)
+    getattr(six.moves.urllib.parse, item_name)
+
+
+@pytest.mark.parametrize("item_name",
+                          [item.name for item in six._urllib_error_moved_attributes])
+def test_move_items_urllib_error(item_name):
+    """Ensure that everything loads correctly."""
+    if sys.version_info[:2] >= (2, 6):
+        assert item_name in dir(six.moves.urllib.error)
+    getattr(six.moves.urllib.error, item_name)
+
+
+@pytest.mark.parametrize("item_name",
+                          [item.name for item in six._urllib_request_moved_attributes])
+def test_move_items_urllib_request(item_name):
+    """Ensure that everything loads correctly."""
+    if sys.version_info[:2] >= (2, 6):
+        assert item_name in dir(six.moves.urllib.request)
+    getattr(six.moves.urllib.request, item_name)
+
+
+@pytest.mark.parametrize("item_name",
+                          [item.name for item in six._urllib_response_moved_attributes])
+def test_move_items_urllib_response(item_name):
+    """Ensure that everything loads correctly."""
+    if sys.version_info[:2] >= (2, 6):
+        assert item_name in dir(six.moves.urllib.response)
+    getattr(six.moves.urllib.response, item_name)
+
+
+@pytest.mark.parametrize("item_name",
+                          [item.name for item in six._urllib_robotparser_moved_attributes])
+def test_move_items_urllib_robotparser(item_name):
+    """Ensure that everything loads correctly."""
+    if sys.version_info[:2] >= (2, 6):
+        assert item_name in dir(six.moves.urllib.robotparser)
+    getattr(six.moves.urllib.robotparser, item_name)
+
+
+def test_import_moves_error_1():
+    from six.moves.urllib.parse import urljoin
+    from six import moves
+    # In 1.4.1: AttributeError: 'Module_six_moves_urllib_parse' object has no attribute 'urljoin'
+    assert moves.urllib.parse.urljoin
+
+
+def test_import_moves_error_2():
+    from six import moves
+    assert moves.urllib.parse.urljoin
+    # In 1.4.1: ImportError: cannot import name urljoin
+    from six.moves.urllib.parse import urljoin
+
+
+def test_import_moves_error_3():
+    from six.moves.urllib.parse import urljoin
+    # In 1.4.1: ImportError: cannot import name urljoin
+    from six.moves.urllib_parse import urljoin
+
+
+def test_from_imports():
+    from six.moves.queue import Queue
+    assert isinstance(Queue, six.class_types)
+    from six.moves.configparser import ConfigParser
+    assert isinstance(ConfigParser, six.class_types)
+
+
+def test_filter():
+    from six.moves import filter
+    f = filter(lambda x: x % 2, range(10))
+    assert six.advance_iterator(f) == 1
+
+
+def test_filter_false():
+    from six.moves import filterfalse
+    f = filterfalse(lambda x: x % 3, range(10))
+    assert six.advance_iterator(f) == 0
+    assert six.advance_iterator(f) == 3
+    assert six.advance_iterator(f) == 6
+
+def test_map():
+    from six.moves import map
+    assert six.advance_iterator(map(lambda x: x + 1, range(2))) == 1
+
+
+def test_getoutput():
+    from six.moves import getoutput
+    output = getoutput('echo "foo"')
+    assert output == 'foo'
+
+
+def test_zip():
+    from six.moves import zip
+    assert six.advance_iterator(zip(range(2), range(2))) == (0, 0)
+
+
+@pytest.mark.skipif("sys.version_info < (2, 6)")
+def test_zip_longest():
+    from six.moves import zip_longest
+    it = zip_longest(range(2), range(1))
+
+    assert six.advance_iterator(it) == (0, 0)
+    assert six.advance_iterator(it) == (1, None)
+
+
+class TestCustomizedMoves:
+
+    def teardown_method(self, meth):
+        try:
+            del six._MovedItems.spam
+        except AttributeError:
+            pass
+        try:
+            del six.moves.__dict__["spam"]
+        except KeyError:
+            pass
+
+
+    def test_moved_attribute(self):
+        attr = six.MovedAttribute("spam", "foo", "bar")
+        if six.PY3:
+            assert attr.mod == "bar"
+        else:
+            assert attr.mod == "foo"
+        assert attr.attr == "spam"
+        attr = six.MovedAttribute("spam", "foo", "bar", "lemma")
+        assert attr.attr == "lemma"
+        attr = six.MovedAttribute("spam", "foo", "bar", "lemma", "theorm")
+        if six.PY3:
+            assert attr.attr == "theorm"
+        else:
+            assert attr.attr == "lemma"
+
+
+    def test_moved_module(self):
+        attr = six.MovedModule("spam", "foo")
+        if six.PY3:
+            assert attr.mod == "spam"
+        else:
+            assert attr.mod == "foo"
+        attr = six.MovedModule("spam", "foo", "bar")
+        if six.PY3:
+            assert attr.mod == "bar"
+        else:
+            assert attr.mod == "foo"
+
+
+    def test_custom_move_module(self):
+        attr = six.MovedModule("spam", "six", "six")
+        six.add_move(attr)
+        six.remove_move("spam")
+        assert not hasattr(six.moves, "spam")
+        attr = six.MovedModule("spam", "six", "six")
+        six.add_move(attr)
+        from six.moves import spam
+        assert spam is six
+        six.remove_move("spam")
+        assert not hasattr(six.moves, "spam")
+
+
+    def test_custom_move_attribute(self):
+        attr = six.MovedAttribute("spam", "six", "six", "u", "u")
+        six.add_move(attr)
+        six.remove_move("spam")
+        assert not hasattr(six.moves, "spam")
+        attr = six.MovedAttribute("spam", "six", "six", "u", "u")
+        six.add_move(attr)
+        from six.moves import spam
+        assert spam is six.u
+        six.remove_move("spam")
+        assert not hasattr(six.moves, "spam")
+
+
+    def test_empty_remove(self):
+        pytest.raises(AttributeError, six.remove_move, "eggs")
+
+
+def test_get_unbound_function():
+    class X(object):
+        def m(self):
+            pass
+    assert six.get_unbound_function(X.m) is X.__dict__["m"]
+
+
+def test_get_method_self():
+    class X(object):
+        def m(self):
+            pass
+    x = X()
+    assert six.get_method_self(x.m) is x
+    pytest.raises(AttributeError, six.get_method_self, 42)
+
+
+def test_get_method_function():
+    class X(object):
+        def m(self):
+            pass
+    x = X()
+    assert six.get_method_function(x.m) is X.__dict__["m"]
+    pytest.raises(AttributeError, six.get_method_function, hasattr)
+
+
+def test_get_function_closure():
+    def f():
+        x = 42
+        def g():
+            return x
+        return g
+    cell = six.get_function_closure(f())[0]
+    assert type(cell).__name__ == "cell"
+
+
+def test_get_function_code():
+    def f():
+        pass
+    assert isinstance(six.get_function_code(f), types.CodeType)
+    if not hasattr(sys, "pypy_version_info"):
+        pytest.raises(AttributeError, six.get_function_code, hasattr)
+
+
+def test_get_function_defaults():
+    def f(x, y=3, b=4):
+        pass
+    assert six.get_function_defaults(f) == (3, 4)
+
+
+def test_get_function_globals():
+    def f():
+        pass
+    assert six.get_function_globals(f) is globals()
+
+
+def test_dictionary_iterators(monkeypatch):
+    def stock_method_name(iterwhat):
+        """Given a method suffix like "lists" or "values", return the name
+        of the dict method that delivers those on the version of Python
+        we're running in."""
+        if six.PY3:
+            return iterwhat
+        return 'iter' + iterwhat
+
+    class MyDict(dict):
+        if not six.PY3:
+            def lists(self, **kw):
+                return [1, 2, 3]
+        def iterlists(self, **kw):
+            return iter([1, 2, 3])
+    f = MyDict.iterlists
+    del MyDict.iterlists
+    setattr(MyDict, stock_method_name('lists'), f)
+
+    d = MyDict(zip(range(10), reversed(range(10))))
+    for name in "keys", "values", "items", "lists":
+        meth = getattr(six, "iter" + name)
+        it = meth(d)
+        assert not isinstance(it, list)
+        assert list(it) == list(getattr(d, name)())
+        pytest.raises(StopIteration, six.advance_iterator, it)
+        record = []
+        def with_kw(*args, **kw):
+            record.append(kw["kw"])
+            return old(*args)
+        old = getattr(MyDict, stock_method_name(name))
+        monkeypatch.setattr(MyDict, stock_method_name(name), with_kw)
+        meth(d, kw=42)
+        assert record == [42]
+        monkeypatch.undo()
+
+
+@pytest.mark.skipif("sys.version_info[:2] < (2, 7)",
+                reason="view methods on dictionaries only available on 2.7+")
+def test_dictionary_views():
+    def stock_method_name(viewwhat):
+        """Given a method suffix like "keys" or "values", return the name
+        of the dict method that delivers those on the version of Python
+        we're running in."""
+        if six.PY3:
+            return viewwhat
+        return 'view' + viewwhat
+
+    d = dict(zip(range(10), (range(11, 20))))
+    for name in "keys", "values", "items":
+        meth = getattr(six, "view" + name)
+        view = meth(d)
+        assert set(view) == set(getattr(d, name)())
+
+
+def test_advance_iterator():
+    assert six.next is six.advance_iterator
+    l = [1, 2]
+    it = iter(l)
+    assert six.next(it) == 1
+    assert six.next(it) == 2
+    pytest.raises(StopIteration, six.next, it)
+    pytest.raises(StopIteration, six.next, it)
+
+
+def test_iterator():
+    class myiter(six.Iterator):
+        def __next__(self):
+            return 13
+    assert six.advance_iterator(myiter()) == 13
+    class myitersub(myiter):
+        def __next__(self):
+            return 14
+    assert six.advance_iterator(myitersub()) == 14
+
+
+def test_callable():
+    class X:
+        def __call__(self):
+            pass
+        def method(self):
+            pass
+    assert six.callable(X)
+    assert six.callable(X())
+    assert six.callable(test_callable)
+    assert six.callable(hasattr)
+    assert six.callable(X.method)
+    assert six.callable(X().method)
+    assert not six.callable(4)
+    assert not six.callable("string")
+
+
+def test_create_bound_method():
+    class X(object):
+        pass
+    def f(self):
+        return self
+    x = X()
+    b = six.create_bound_method(f, x)
+    assert isinstance(b, types.MethodType)
+    assert b() is x
+
+
+def test_create_unbound_method():
+    class X(object):
+        pass
+
+    def f(self):
+        return self
+    u = six.create_unbound_method(f, X)
+    pytest.raises(TypeError, u)
+    if six.PY2:
+        assert isinstance(u, types.MethodType)
+    x = X()
+    assert f(x) is x
+
+
+if six.PY3:
+
+    def test_b():
+        data = six.b("\xff")
+        assert isinstance(data, bytes)
+        assert len(data) == 1
+        assert data == bytes([255])
+
+
+    def test_u():
+        s = six.u("hi \u0439 \U00000439 \\ \\\\ \n")
+        assert isinstance(s, str)
+        assert s == "hi \u0439 \U00000439 \\ \\\\ \n"
+
+else:
+
+    def test_b():
+        data = six.b("\xff")
+        assert isinstance(data, str)
+        assert len(data) == 1
+        assert data == "\xff"
+
+
+    def test_u():
+        s = six.u("hi \u0439 \U00000439 \\ \\\\ \n")
+        assert isinstance(s, unicode)
+        assert s == "hi \xd0\xb9 \xd0\xb9 \\ \\\\ \n".decode("utf8")
+
+
+def test_u_escapes():
+    s = six.u("\u1234")
+    assert len(s) == 1
+
+
+def test_unichr():
+    assert six.u("\u1234") == six.unichr(0x1234)
+    assert type(six.u("\u1234")) is type(six.unichr(0x1234))
+
+
+def test_int2byte():
+    assert six.int2byte(3) == six.b("\x03")
+    pytest.raises(Exception, six.int2byte, 256)
+
+
+def test_byte2int():
+    assert six.byte2int(six.b("\x03")) == 3
+    assert six.byte2int(six.b("\x03\x04")) == 3
+    pytest.raises(IndexError, six.byte2int, six.b(""))
+
+
+def test_bytesindex():
+    assert six.indexbytes(six.b("hello"), 3) == ord("l")
+
+
+def test_bytesiter():
+    it = six.iterbytes(six.b("hi"))
+    assert six.next(it) == ord("h")
+    assert six.next(it) == ord("i")
+    pytest.raises(StopIteration, six.next, it)
+
+
+def test_StringIO():
+    fp = six.StringIO()
+    fp.write(six.u("hello"))
+    assert fp.getvalue() == six.u("hello")
+
+
+def test_BytesIO():
+    fp = six.BytesIO()
+    fp.write(six.b("hello"))
+    assert fp.getvalue() == six.b("hello")
+
+
+def test_exec_():
+    def f():
+        l = []
+        six.exec_("l.append(1)")
+        assert l == [1]
+    f()
+    ns = {}
+    six.exec_("x = 42", ns)
+    assert ns["x"] == 42
+    glob = {}
+    loc = {}
+    six.exec_("global y; y = 42; x = 12", glob, loc)
+    assert glob["y"] == 42
+    assert "x" not in glob
+    assert loc["x"] == 12
+    assert "y" not in loc
+
+
+def test_reraise():
+    def get_next(tb):
+        if six.PY3:
+            return tb.tb_next.tb_next
+        else:
+            return tb.tb_next
+    e = Exception("blah")
+    try:
+        raise e
+    except Exception:
+        tp, val, tb = sys.exc_info()
+    try:
+        six.reraise(tp, val, tb)
+    except Exception:
+        tp2, value2, tb2 = sys.exc_info()
+        assert tp2 is Exception
+        assert value2 is e
+        assert tb is get_next(tb2)
+    try:
+        six.reraise(tp, val)
+    except Exception:
+        tp2, value2, tb2 = sys.exc_info()
+        assert tp2 is Exception
+        assert value2 is e
+        assert tb2 is not tb
+    try:
+        six.reraise(tp, val, tb2)
+    except Exception:
+        tp2, value2, tb3 = sys.exc_info()
+        assert tp2 is Exception
+        assert value2 is e
+        assert get_next(tb3) is tb2
+    try:
+        six.reraise(tp, None, tb)
+    except Exception:
+        tp2, value2, tb2 = sys.exc_info()
+        assert tp2 is Exception
+        assert value2 is not val
+        assert isinstance(value2, Exception)
+        assert tb is get_next(tb2)
+
+
+def test_raise_from():
+    try:
+        try:
+            raise Exception("blah")
+        except Exception:
+            ctx = sys.exc_info()[1]
+            f = Exception("foo")
+            six.raise_from(f, None)
+    except Exception:
+        tp, val, tb = sys.exc_info()
+    if sys.version_info[:2] > (3, 0):
+        # We should have done a raise f from None equivalent.
+        assert val.__cause__ is None
+        assert val.__context__ is ctx
+    if sys.version_info[:2] >= (3, 3):
+        # And that should suppress the context on the exception.
+        assert val.__suppress_context__
+    # For all versions the outer exception should have raised successfully.
+    assert str(val) == "foo"
+
+
+def test_print_():
+    save = sys.stdout
+    out = sys.stdout = six.moves.StringIO()
+    try:
+        six.print_("Hello,", "person!")
+    finally:
+        sys.stdout = save
+    assert out.getvalue() == "Hello, person!\n"
+    out = six.StringIO()
+    six.print_("Hello,", "person!", file=out)
+    assert out.getvalue() == "Hello, person!\n"
+    out = six.StringIO()
+    six.print_("Hello,", "person!", file=out, end="")
+    assert out.getvalue() == "Hello, person!"
+    out = six.StringIO()
+    six.print_("Hello,", "person!", file=out, sep="X")
+    assert out.getvalue() == "Hello,Xperson!\n"
+    out = six.StringIO()
+    six.print_(six.u("Hello,"), six.u("person!"), file=out)
+    result = out.getvalue()
+    assert isinstance(result, six.text_type)
+    assert result == six.u("Hello, person!\n")
+    six.print_("Hello", file=None) # This works.
+    out = six.StringIO()
+    six.print_(None, file=out)
+    assert out.getvalue() == "None\n"
+    class FlushableStringIO(six.StringIO):
+        def __init__(self):
+            six.StringIO.__init__(self)
+            self.flushed = False
+        def flush(self):
+            self.flushed = True
+    out = FlushableStringIO()
+    six.print_("Hello", file=out)
+    assert not out.flushed
+    six.print_("Hello", file=out, flush=True)
+    assert out.flushed
+
+
+@pytest.mark.skipif("sys.version_info[:2] >= (2, 6)")
+def test_print_encoding(monkeypatch):
+    # Fool the type checking in print_.
+    monkeypatch.setattr(six, "file", six.BytesIO, raising=False)
+    out = six.BytesIO()
+    out.encoding = "utf-8"
+    out.errors = None
+    six.print_(six.u("\u053c"), end="", file=out)
+    assert out.getvalue() == six.b("\xd4\xbc")
+    out = six.BytesIO()
+    out.encoding = "ascii"
+    out.errors = "strict"
+    pytest.raises(UnicodeEncodeError, six.print_, six.u("\u053c"), file=out)
+    out.errors = "backslashreplace"
+    six.print_(six.u("\u053c"), end="", file=out)
+    assert out.getvalue() == six.b("\\u053c")
+
+
+def test_print_exceptions():
+    pytest.raises(TypeError, six.print_, x=3)
+    pytest.raises(TypeError, six.print_, end=3)
+    pytest.raises(TypeError, six.print_, sep=42)
+
+
+def test_with_metaclass():
+    class Meta(type):
+        pass
+    class X(six.with_metaclass(Meta)):
+        pass
+    assert type(X) is Meta
+    assert issubclass(X, object)
+    class Base(object):
+        pass
+    class X(six.with_metaclass(Meta, Base)):
+        pass
+    assert type(X) is Meta
+    assert issubclass(X, Base)
+    class Base2(object):
+        pass
+    class X(six.with_metaclass(Meta, Base, Base2)):
+        pass
+    assert type(X) is Meta
+    assert issubclass(X, Base)
+    assert issubclass(X, Base2)
+    assert X.__mro__ == (X, Base, Base2, object)
+    class X(six.with_metaclass(Meta)):
+        pass
+    class MetaSub(Meta):
+        pass
+    class Y(six.with_metaclass(MetaSub, X)):
+        pass
+    assert type(Y) is MetaSub
+    assert Y.__mro__ == (Y, X, object)
+
+
+@pytest.mark.skipif("sys.version_info[:2] < (2, 7)")
+def test_with_metaclass_typing():
+    try:
+        import typing
+    except ImportError:
+        pytest.skip("typing module required")
+    class Meta(type):
+        pass
+    if sys.version_info[:2] < (3, 7):
+        # Generics with custom metaclasses were broken on older versions.
+        class Meta(Meta, typing.GenericMeta):
+            pass
+    T = typing.TypeVar('T')
+    class G(six.with_metaclass(Meta, typing.Generic[T])):
+        pass
+    class GA(six.with_metaclass(abc.ABCMeta, typing.Generic[T])):
+        pass
+    assert isinstance(G, Meta)
+    assert isinstance(GA, abc.ABCMeta)
+    assert G[int] is not G[G[int]]
+    assert GA[int] is not GA[GA[int]]
+    assert G.__bases__ == (typing.Generic,)
+    assert G.__orig_bases__ == (typing.Generic[T],)
+
+
+@pytest.mark.skipif("sys.version_info[:2] < (3, 7)")
+def test_with_metaclass_pep_560():
+    class Meta(type):
+        pass
+    class A:
+        pass
+    class B:
+        pass
+    class Fake:
+        def __mro_entries__(self, bases):
+            return (A, B)
+    fake = Fake()
+    class G(six.with_metaclass(Meta, fake)):
+        pass
+    class GA(six.with_metaclass(abc.ABCMeta, fake)):
+        pass
+    assert isinstance(G, Meta)
+    assert isinstance(GA, abc.ABCMeta)
+    assert G.__bases__ == (A, B)
+    assert G.__orig_bases__ == (fake,)
+
+
+@pytest.mark.skipif("sys.version_info[:2] < (3, 0)")
+def test_with_metaclass_prepare():
+    """Test that with_metaclass causes Meta.__prepare__ to be called with the correct arguments."""
+
+    class MyDict(dict):
+        pass
+
+    class Meta(type):
+
+        @classmethod
+        def __prepare__(cls, name, bases):
+            namespace = MyDict(super().__prepare__(name, bases), cls=cls, bases=bases)
+            namespace['namespace'] = namespace
+            return namespace
+
+    class Base(object):
+        pass
+
+    bases = (Base,)
+
+    class X(six.with_metaclass(Meta, *bases)):
+        pass
+
+    assert getattr(X, 'cls', type) is Meta
+    assert getattr(X, 'bases', ()) == bases
+    assert isinstance(getattr(X, 'namespace', {}), MyDict)
+
+
+def test_wraps():
+    def f(g):
+        @six.wraps(g)
+        def w():
+            return 42
+        return w
+    def k():
+        pass
+    original_k = k
+    k = f(f(k))
+    assert hasattr(k, '__wrapped__')
+    k = k.__wrapped__
+    assert hasattr(k, '__wrapped__')
+    k = k.__wrapped__
+    assert k is original_k
+    assert not hasattr(k, '__wrapped__')
+
+    def f(g, assign, update):
+        def w():
+            return 42
+        w.glue = {"foo" : "bar"}
+        return six.wraps(g, assign, update)(w)
+    k.glue = {"melon" : "egg"}
+    k.turnip = 43
+    k = f(k, ["turnip"], ["glue"])
+    assert k.__name__ == "w"
+    assert k.turnip == 43
+    assert k.glue == {"melon" : "egg", "foo" : "bar"}
+
+
+def test_add_metaclass():
+    class Meta(type):
+        pass
+    class X:
+        "success"
+    X = six.add_metaclass(Meta)(X)
+    assert type(X) is Meta
+    assert issubclass(X, object)
+    assert X.__module__ == __name__
+    assert X.__doc__ == "success"
+    class Base(object):
+        pass
+    class X(Base):
+        pass
+    X = six.add_metaclass(Meta)(X)
+    assert type(X) is Meta
+    assert issubclass(X, Base)
+    class Base2(object):
+        pass
+    class X(Base, Base2):
+        pass
+    X = six.add_metaclass(Meta)(X)
+    assert type(X) is Meta
+    assert issubclass(X, Base)
+    assert issubclass(X, Base2)
+
+    # Test a second-generation subclass of a type.
+    class Meta1(type):
+        m1 = "m1"
+    class Meta2(Meta1):
+        m2 = "m2"
+    class Base:
+        b = "b"
+    Base = six.add_metaclass(Meta1)(Base)
+    class X(Base):
+        x = "x"
+    X = six.add_metaclass(Meta2)(X)
+    assert type(X) is Meta2
+    assert issubclass(X, Base)
+    assert type(Base) is Meta1
+    assert "__dict__" not in vars(X)
+    instance = X()
+    instance.attr = "test"
+    assert vars(instance) == {"attr": "test"}
+    assert instance.b == Base.b
+    assert instance.x == X.x
+
+    # Test a class with slots.
+    class MySlots(object):
+        __slots__ = ["a", "b"]
+    MySlots = six.add_metaclass(Meta1)(MySlots)
+
+    assert MySlots.__slots__ == ["a", "b"]
+    instance = MySlots()
+    instance.a = "foo"
+    pytest.raises(AttributeError, setattr, instance, "c", "baz")
+
+    # Test a class with string for slots.
+    class MyStringSlots(object):
+        __slots__ = "ab"
+    MyStringSlots = six.add_metaclass(Meta1)(MyStringSlots)
+    assert MyStringSlots.__slots__ == "ab"
+    instance = MyStringSlots()
+    instance.ab = "foo"
+    pytest.raises(AttributeError, setattr, instance, "a", "baz")
+    pytest.raises(AttributeError, setattr, instance, "b", "baz")
+
+    class MySlotsWeakref(object):
+        __slots__ = "__weakref__",
+    MySlotsWeakref = six.add_metaclass(Meta)(MySlotsWeakref)
+    assert type(MySlotsWeakref) is Meta
+
+
+@pytest.mark.skipif("sys.version_info[:2] < (3, 3)")
+def test_add_metaclass_nested():
+    # Regression test for https://github.com/benjaminp/six/issues/259
+    class Meta(type):
+        pass
+
+    class A:
+        class B: pass
+
+    expected = 'test_add_metaclass_nested.<locals>.A.B'
+
+    assert A.B.__qualname__ == expected
+
+    class A:
+        @six.add_metaclass(Meta)
+        class B: pass
+
+    assert A.B.__qualname__ == expected
+
+
+@pytest.mark.skipif("sys.version_info[:2] < (2, 7) or sys.version_info[:2] in ((3, 0), (3, 1))")
+def test_assertCountEqual():
+    class TestAssertCountEqual(unittest.TestCase):
+        def test(self):
+            with self.assertRaises(AssertionError):
+                six.assertCountEqual(self, (1, 2), [3, 4, 5])
+
+            six.assertCountEqual(self, (1, 2), [2, 1])
+
+    TestAssertCountEqual('test').test()
+
+
+@pytest.mark.skipif("sys.version_info[:2] < (2, 7)")
+def test_assertRegex():
+    class TestAssertRegex(unittest.TestCase):
+        def test(self):
+            with self.assertRaises(AssertionError):
+                six.assertRegex(self, 'test', r'^a')
+
+            six.assertRegex(self, 'test', r'^t')
+
+    TestAssertRegex('test').test()
+
+
+@pytest.mark.skipif("sys.version_info[:2] < (2, 7)")
+def test_assertRaisesRegex():
+    class TestAssertRaisesRegex(unittest.TestCase):
+        def test(self):
+            with six.assertRaisesRegex(self, AssertionError, '^Foo'):
+                raise AssertionError('Foo')
+
+            with self.assertRaises(AssertionError):
+                with six.assertRaisesRegex(self, AssertionError, r'^Foo'):
+                    raise AssertionError('Bar')
+
+    TestAssertRaisesRegex('test').test()
+
+
+def test_python_2_unicode_compatible():
+    @six.python_2_unicode_compatible
+    class MyTest(object):
+        def __str__(self):
+            return six.u('hello')
+
+        def __bytes__(self):
+            return six.b('hello')
+
+    my_test = MyTest()
+
+    if six.PY2:
+        assert str(my_test) == six.b("hello")
+        assert unicode(my_test) == six.u("hello")
+    elif six.PY3:
+        assert bytes(my_test) == six.b("hello")
+        assert str(my_test) == six.u("hello")
+
+    assert getattr(six.moves.builtins, 'bytes', str)(my_test) == six.b("hello")
+
+
+class EnsureTests:
+
+    # grinning face emoji
+    UNICODE_EMOJI = six.u("\U0001F600")
+    BINARY_EMOJI = b"\xf0\x9f\x98\x80"
+
+    def test_ensure_binary_raise_type_error(self):
+        with pytest.raises(TypeError):
+            six.ensure_str(8)
+
+    def test_errors_and_encoding(self):
+        six.ensure_binary(self.UNICODE_EMOJI, encoding='latin-1', errors='ignore')
+        with pytest.raises(UnicodeEncodeError):
+            six.ensure_binary(self.UNICODE_EMOJI, encoding='latin-1', errors='strict')
+
+    def test_ensure_binary_raise(self):
+        converted_unicode = six.ensure_binary(self.UNICODE_EMOJI, encoding='utf-8', errors='strict')
+        converted_binary = six.ensure_binary(self.BINARY_EMOJI, encoding="utf-8", errors='strict')
+        if six.PY2:
+            # PY2: unicode -> str
+            assert converted_unicode == self.BINARY_EMOJI and isinstance(converted_unicode, str)
+            # PY2: str -> str
+            assert converted_binary == self.BINARY_EMOJI and isinstance(converted_binary, str)
+        else:
+            # PY3: str -> bytes
+            assert converted_unicode == self.BINARY_EMOJI and isinstance(converted_unicode, bytes)
+            # PY3: bytes -> bytes
+            assert converted_binary == self.BINARY_EMOJI and isinstance(converted_binary, bytes)
+
+    def test_ensure_str(self):
+        converted_unicode = six.ensure_str(self.UNICODE_EMOJI, encoding='utf-8', errors='strict')
+        converted_binary = six.ensure_str(self.BINARY_EMOJI, encoding="utf-8", errors='strict')
+        if six.PY2:
+            # PY2: unicode -> str
+            assert converted_unicode == self.BINARY_EMOJI and isinstance(converted_unicode, str)
+            # PY2: str -> str
+            assert converted_binary == self.BINARY_EMOJI and isinstance(converted_binary, str)
+        else:
+            # PY3: str -> str
+            assert converted_unicode == self.UNICODE_EMOJI and isinstance(converted_unicode, str)
+            # PY3: bytes -> str
+            assert converted_binary == self.UNICODE_EMOJI and isinstance(converted_unicode, str)
+
+    def test_ensure_text(self):
+        converted_unicode = six.ensure_text(self.UNICODE_EMOJI, encoding='utf-8', errors='strict')
+        converted_binary = six.ensure_text(self.BINARY_EMOJI, encoding="utf-8", errors='strict')
+        if six.PY2:
+            # PY2: unicode -> unicode
+            assert converted_unicode == self.UNICODE_EMOJI and isinstance(converted_unicode, unicode)
+            # PY2: str -> unicode
+            assert converted_binary == self.UNICODE_EMOJI and isinstance(converted_unicode, unicode)
+        else:
+            # PY3: str -> str
+            assert converted_unicode == self.UNICODE_EMOJI and isinstance(converted_unicode, str)
+            # PY3: bytes -> str
+            assert converted_binary == self.UNICODE_EMOJI and isinstance(converted_unicode, str)