'Parse an HTTP date, like \'Fri, 31 Dec 1999 23:59:59 GMT\'.
Return an epoch timestamp (float), as returned by time.mktime().'

def _parse_http_date(self, val):

    parts = email.utils.parsedate(val)
    if (not parts):
        raise ValueError(('Failed    to    parse    date    %s' % val))
    return time.mktime(parts)
