'Calculate a date by treating the current L{SerialNumber} value as a UNIX
timestamp and return a date string in the format described in
U{RFC4034 3.2<https://tools.ietf.org/html/rfc4034#section-3.2>}.
@return: The date string.'

def toRFC4034DateString(self):

    d = (datetime(1970, 1, 1) + timedelta(seconds=self._number))
    return nativeString(d.strftime(RFC4034_TIME_FORMAT))
