def rename_legacy_cols(df):
    """Renames columns of dataframe in format consistent with the current naming scheme"""
    return df.rename(
        columns={'Start date':'started_at',
                 'End date': 'ended_at',
                 'Start station':'start_station_name',
                 'End station': 'end_station_name',
                 'Member type': 'member_casual'}
    )