Find similar objects using related tags.

def similar_objects(self, num=None, **filters):
        """
        Find similar objects using related tags.
        """
        # TODO: filter appsettings.FLUENT_BLOGS_FILTER_SITE_ID:
        #    filters.setdefault('parent_site', self.parent_site_id)

        # FIXME: Using super() doesn't work, calling directly.
        return TagsMixin.similar_objects(self, num=num, **filters)