@classmethod
def httpdate(cls, dt):
    """Return a string representation of a date according to RFC 1123
        (HTTP/1.1).

        The supplied date must be in UTC.
        """
    weekday = ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun'][dt.weekday()]
    month = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep',
        'Oct', 'Nov', 'Dec'][dt.month - 1]
    return '%s, %02d %s %04d %02d:%02d:%02d GMT' % (weekday, dt.day, month,
        dt.year, dt.hour, dt.minute, dt.second)
