This will return a summary record for each message in a particular
        category. (Note that a summary record includes only a few bits of
        information about a post, not the complete record.)

def message_archive_per_category(self, project_id, category_id):
        """
        This will return a summary record for each message in a particular
        category. (Note that a summary record includes only a few bits of
        information about a post, not the complete record.)
        """
        path = '/projects/%u/msg/cat/%u/archive' % (project_id, category_id)
        return self._request(path)