code: def test_insert(self):
      pidx = pd.CategoricalIndex(
          ["x", "y", "z"], categories=["z", "y", "x", "w"]
      )
      psidx = ps.from_pandas(pidx)
  
      self.assert_eq(psidx.insert(1, "w"), pidx.insert(1, "w"))
  
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 13 for calling the CategoricalIndexTestsMixin obj's underlying member method code with example usage: obj.test_insert() without return types