code: def test_factorize(self):
      pidx = pd.CategoricalIndex([1, 2, 3, None])
      psidx = ps.from_pandas(pidx)
  
      pcodes, puniques = pidx.factorize()
      kcodes, kuniques = psidx.factorize()
  
      self.assert_eq(kcodes.tolist(), pcodes.tolist())
      self.assert_eq(kuniques, puniques)
  
      pcodes, puniques = pidx.factorize(use_na_sentinel=-2)
      kcodes, kuniques = psidx.factorize(use_na_sentinel=-2)
  
      self.assert_eq(kcodes.tolist(), pcodes.tolist())
      self.assert_eq(kuniques, puniques)
  
imports: import unittest
  import pandas
  from pandas.api.types import CategoricalDtype
  import pyspark.pandas
  from pyspark.loose_version import LooseVersion
  from pyspark.testing.pandasutils import PandasOnSparkTestCase, TestUtils
label_desc: Use image node_id 9 for calling the CategoricalIndexTestsMixin obj's underlying member method code with example usage: obj.test_factorize() without return types