Modified top-level name object on CategoricalDtype class by importing the set module decorator and decorating the class. Tested the modification by adding an assert statement to the already existing test_set_module test function

Author: Amir

pandas/core/dtypes/dtypes.py

@@ -48,6 +48,7 @@
 from pandas._libs.tslibs.offsets import BDay
 from pandas.compat import pa_version_under10p1
 from pandas.errors import PerformanceWarning
+from pandas.util._decorators import set_module
 from pandas.util._exceptions import find_stack_level
 
 from pandas.core.dtypes.base import (
@@ -155,6 +156,7 @@ class CategoricalDtypeType(type):
 
 
 @register_extension_dtype
+@set_module("pandas")
 class CategoricalDtype(PandasExtensionDtype, ExtensionDtype):
     """
     Type for categorical data with the categories and orderedness.

pandas/tests/api/test_api.py

@@ -400,3 +400,4 @@ def test_util_in_top_level(self):
 
 def test_set_module():
     assert pd.DataFrame.__module__ == "pandas"
+    assert pd.CategoricalDtype.__module__ == "pandas"