code: def test_contains(self):
      ci = CategoricalIndex(
          list("aabbca"), categories=list("cabdef"), ordered=False
      )
  
      assert "a" in ci
      assert "z" not in ci
      assert "e" not in ci
      assert np.nan not in ci
  
      # assert codes NOT in index
      assert 0 not in ci
      assert 1 not in ci
  
imports: import numpy
  import pytest
  from pandas.errors import InvalidIndexError
  import pandas
  from pandas import CategoricalIndex, Index, IntervalIndex, Timestamp
  import pandas._testing
label_desc: Use image node_id 1 for calling the TestContains obj's underlying member method code with example usage: obj.test_contains() without return types