code: def test_categorical_dtype(self):
      ce = dpp.Categorizer()
      ce.fit(raw)
      assert hash(ce.categories_["A"]) == hash(
          pd.api.types.CategoricalDtype(["a", "b", "c"], False)
      )
  
imports: from copy import copy
  import dask
  import dask.array
  import dask.dataframe
  import numpy
  import pandas
  import pandas.testing
  import pytest
  import sklearn.preprocessing
  from dask import compute
  from dask.array.utils import assert_eq
  from dask.dataframe.utils import assert_eq
  from pandas.api.types import is_categorical_dtype, is_object_dtype
  from sklearn.exceptions import NotFittedError
  import dask_ml.preprocessing
  from dask_ml.datasets import make_classification
  from dask_ml.utils import assert_estimator_equal
label_desc: Use image node_id 6 for calling the TestCategorizer obj's underlying member method code with example usage: obj.test_categorical_dtype() without return types