def datetime_to_time(date, time):
    """Take the date and time 4-tuples and return the time in seconds since
    the epoch as a floating point number."""
    if (255 in date) or (255 in time):
        raise RuntimeError("specific date and time required")

    time_tuple = (
        date[0]+1900, date[1], date[2],
        time[0], time[1], time[2],
        0, 0, -1,
        )
    return _mktime(time_tuple)
Take the date and time 4-tuples and return the time in seconds since
    the epoch as a floating point number.