def _check_if_index_name_in_cols(df):
    """
    Check if existing index is in the passed dataframe list of column names

    Parameters
    ----------
    df : pandas.DataFrame
        interpolated stop_time dataframe

    Returns
    -------
    iname : tuple
    """
    cols = df.columns.values
    iname = df.index.name
    return iname in cols
