def list(self, **kwargs):
        """
        Returns a list of :class:`MessagingStat` objects (messaging statistics).

        :Example:

        stats = client.stats_messaging.list()

        :param str by:    Group results by specified period: `off`, `day`, `month` or `year`. Default is `off`.
        :param str start: Start date in unix timestamp format. Default is 7 days ago.
        :param str end:   End date in unix timestamp format. Default is now.
        """
        response, instances = self.request("GET", self.uri, params=kwargs)
        return [self.load_instance(r) for r in instances]
Returns a list of :class:`MessagingStat` objects (messaging statistics).

        :Example:

        stats = client.stats_messaging.list()

        :param str by:    Group results by specified period: `off`, `day`, `month` or `year`. Default is `off`.
        :param str start: Start date in unix timestamp format. Default is 7 days ago.
        :param str end:   End date in unix timestamp format. Default is now.