code: def test_astype_categorical_invalid_conversions(self):
      # invalid conversion (these are NOT a dtype)
      cat = Categorical(
          [f"{i} - {i + 499}" for i in range(0, 10000, 500)]
      )
      ser = Series(
          np.random.default_rng(2).integers(0, 10000, 100)
      ).sort_values()
      ser = cut(ser, range(0, 10500, 500), right=False, labels=cat)
  
      msg = (
          "dtype '<class 'pandas.core.arrays.categorical.Categorical'>' "
          "not understood"
      )
      with pytest.raises(TypeError, match=msg):
          ser.astype(Categorical)
      with pytest.raises(TypeError, match=msg):
          ser.astype("object").astype(Categorical)
  
imports: from datetime import datetime, timedelta
  from importlib import reload
  import string
  import sys
  import numpy
  import pytest
  from pandas._libs.tslibs import iNaT
  import pandas.util._test_decorators
  from pandas import NA, Categorical, CategoricalDtype, DatetimeTZDtype, Index, Interval, NaT, Series, Timedelta, Timestamp, cut, date_range, to_datetime
  import pandas._testing
label_desc: Use image node_id 2 for calling the TestAstypeCategorical obj's underlying member method code with example usage: obj.test_astype_categorical_invalid_conversions() without return types