@staticmethod
def save_df(data_df, outfile_path_str: str, keep_index_b=False, sep=','
    ) ->None:
    """
        By default don't keep the index, it is just annoying.

        Parameters
        ----------
        data_df
        outfile_path_str
        keep_index_b
        sep

        Returns
        -------

        """
    data_df.to_csv(outfile_path_str, index=keep_index_b, sep=sep)
