code: def test_set_dtype_no_overlap(self):
      c = Categorical(["a", "b", "c"], ["d", "e"])
      result = c._set_dtype(CategoricalDtype(["a", "b"]))
      expected = Categorical([None, None, None], categories=["a", "b"])
      tm.assert_categorical_equal(result, expected)
  
file_path: pandas/pandas/tests/arrays/categorical/test_dtypes.py
imports: import numpy
  import pytest
  from pandas.core.dtypes.dtypes import CategoricalDtype
  from pandas import Categorical, CategoricalIndex, Index, IntervalIndex, Series, Timestamp
  import pandas._testing
label_desc: Use image node_id 5 for calling the TestCategoricalDtypes obj's underlying member method code with example usage: obj.test_set_dtype_no_overlap() without return types