def get_sunset_time(self, timeformat='unix'):
        """Returns the GMT time of sunset

        :param timeformat: the format for the time value. May be:
            '*unix*' (default) for UNIX time or '*iso*' for ISO8601-formatted
            string in the format ``YYYY-MM-DD HH:MM:SS+00``
        :type timeformat: str
        :returns: an int or a str or None
        :raises: ValueError

        """
        if self._sunset_time is None:
            return None
        return timeformatutils.timeformat(self._sunset_time, timeformat)
Returns the GMT time of sunset

        :param timeformat: the format for the time value. May be:
            '*unix*' (default) for UNIX time or '*iso*' for ISO8601-formatted
            string in the format ``YYYY-MM-DD HH:MM:SS+00``
        :type timeformat: str
        :returns: an int or a str or None
        :raises: ValueError