1 files changed, 38 insertions, 7 deletions
diff --git a/sqlglot/helper.py b/sqlglot/helper.py
index 379c2e7..8c5808d 100644
--- a/sqlglot/helper.py
+++ b/sqlglot/helper.py
@@ -11,7 +11,8 @@ from copy import copy
 from enum import Enum
 
 if t.TYPE_CHECKING:
-    from sqlglot.expressions import Expression, Table
+    from sqlglot import exp
+    from sqlglot.expressions import Expression
 
     T = t.TypeVar("T")
     E = t.TypeVar("E", bound=Expression)
@@ -150,7 +151,7 @@ def apply_index_offset(expressions: t.List[E], offset: int) -> t.List[E]:
     if expression.is_int:
         expression = expression.copy()
         logger.warning("Applying array index offset (%s)", offset)
-        expression.args["this"] = str(int(expression.args["this"]) + offset)
+        expression.args["this"] = str(int(expression.this) + offset)
         return [expression]
 
     return expressions
@@ -228,19 +229,18 @@ def open_file(file_name: str) -> t.TextIO:
 
 
 @contextmanager
-def csv_reader(table: Table) -> t.Any:
+def csv_reader(read_csv: exp.ReadCSV) -> t.Any:
     """
     Returns a csv reader given the expression `READ_CSV(name, ['delimiter', '|', ...])`.
 
     Args:
-        table: a `Table` expression with an anonymous function `READ_CSV` in it.
+        read_csv: a `ReadCSV` function call
 
     Yields:
         A python csv reader.
     """
-    file, *args = table.this.expressions
-    file = file.name
-    file = open_file(file)
+    args = read_csv.expressions
+    file = open_file(read_csv.name)
 
     delimiter = ","
     args = iter(arg.name for arg in args)
@@ -354,3 +354,34 @@ def flatten(values: t.Iterable[t.Iterable[t.Any] | t.Any]) -> t.Generator[t.Any,
             yield from flatten(value)
         else:
             yield value
+
+
+def dict_depth(d: t.Dict) -> int:
+    """
+    Get the nesting depth of a dictionary.
+
+    For example:
+        >>> dict_depth(None)
+        0
+        >>> dict_depth({})
+        1
+        >>> dict_depth({"a": "b"})
+        1
+        >>> dict_depth({"a": {}})
+        2
+        >>> dict_depth({"a": {"b": {}}})
+        3
+
+    Args:
+        d (dict): dictionary
+    Returns:
+        int: depth
+    """
+    try:
+        return 1 + dict_depth(next(iter(d.values())))
+    except AttributeError:
+        # d doesn't have attribute "values"
+        return 0
+    except StopIteration:
+        # d.values() returns an empty sequence
+        return 1