def METHOD_NAME(input_df_1, input_df_2, input_df_3):
    assert isinstance(input_df_1, pd.DataFrame)
    assert isinstance(input_df_2, pd.DataFrame)
    assert isinstance(input_df_3, pd.DataFrame)
    assert all(x.isupper() for x in list(input_df_1.columns))
    assert all(x.islower() for x in list(input_df_2.columns))
    assert all(x.islower() for x in list(input_df_3.columns))