def last_update_time(self, timeformat='unix'):
        """Returns the UTC time of the last update on this station's metadata

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

        """
        if self.updated_at is None:
            return None
        return timeformatutils.timeformat(self.updated_at, timeformat)
Returns the UTC time of the last update on this station's metadata

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