def as_iso8601(self):
        """
        example: 2016-08-13T00:38:05.210+00:00
        """
        if self.__date is None or self.__time is None:
            return None

        return "20%s-%s-%sT%s:%s:%s0Z" % \
               (self.__date[4:], self.__date[2:4], self.__date[:2], self.__time[:2], self.__time[2:4], self.__time[4:])