1 files changed, 50 insertions, 0 deletions
diff --git a/treelib/exceptions.py b/treelib/exceptions.py
new file mode 100644
index 0000000..fc955c5
--- /dev/null
+++ b/treelib/exceptions.py
@@ -0,0 +1,50 @@
+class NodePropertyError(Exception):
+    """Basic Node attribute error"""
+
+    pass
+
+
+class NodeIDAbsentError(NodePropertyError):
+    """Exception throwed if a node's identifier is unknown"""
+
+    pass
+
+
+class NodePropertyAbsentError(NodePropertyError):
+    """Exception throwed if a node's data property is not specified"""
+
+    pass
+
+
+class MultipleRootError(Exception):
+    """Exception throwed if more than one root exists in a tree."""
+
+    pass
+
+
+class DuplicatedNodeIdError(Exception):
+    """Exception throwed if an identifier already exists in a tree."""
+
+    pass
+
+
+class LinkPastRootNodeError(Exception):
+    """
+    Exception throwed in Tree.link_past_node() if one attempts
+    to "link past" the root node of a tree.
+    """
+
+    pass
+
+
+class InvalidLevelNumber(Exception):
+    pass
+
+
+class LoopError(Exception):
+    """
+    Exception thrown if trying to move node B to node A's position
+    while A is B's ancestor.
+    """
+
+    pass