code: def test_clean_names_camelcase_to_snake(dataframe):
      """Tests clean_names `case_type` parameter = snake."""
      df = (
          dataframe.select(columns=["a"])
          .rename_column("a", "AColumnName")
          .clean_names(case_type="snake")
      )
      assert list(df.columns) == ["a_column_name"]
  
file_path: pyjanitor/tests/functions/test_clean_names.py
imports: import pandas
  import pytest
  from janitor.errors import JanitorError
label_desc: Use image node_id 10 for calling a global function with example usage: test_clean_names_camelcase_to_snake(dataframe) without return types