def filter_generic(self, content_object=None, **kwargs):
        """Filter by a generic object.

        :param content_object: the content object to filter on.
        """
        if content_object:
            kwargs['content_type'] = ContentType.objects.get_for_model(
                content_object
            )
            kwargs['object_id'] = content_object.id

        return self.filter(**kwargs)