code: def pdf(self):
      return pd.DataFrame(
          {
              "a": pd.Categorical([1, 2, 3, 1, 2, 3]),
              "b": pd.Categorical(
                  ["b", "a", "c", "c", "b", "a"],
                  categories=["c", "b", "d", "a"],
              ),
          },
      )
  
imports: import numpy
  import pandas
  from pandas.api.types import CategoricalDtype
  import pyspark.pandas
  from pyspark.testing.pandasutils import ComparisonTestBase, TestUtils
label_desc: Use image node_id 1 for calling the CategoricalTestsMixin obj's underlying member method code with example usage: obj.pdf() and returns: pd