code: def test_type_dict_single_index(df):
      """Raise TypeError if dtype is a dict and single index."""
      msg = "Changing the dtype via a dictionary "
      msg = "is not supported for a single index."
      with pytest.raises(TypeError, match=msg):
          df.change_index_dtype(dtype={0: float})
  
file_path: pyjanitor/tests/functions/test_change_index_dtype.py
imports: import numpy
  import pandas
  import pytest
  from pandas.testing import assert_frame_equal
label_desc: Use image node_id 5 for calling a global function with example usage: test_type_dict_single_index(df) without return types