public function get_legacy_data_mapper_for_vault($entity) {
        switch($entity) {
            case 'forum':
                return $this->get_forum_data_mapper();
            case 'discussion':
                return $this->get_discussion_data_mapper();
            case 'post':
                return $this->get_post_data_mapper();
            case 'author':
                return $this->get_author_data_mapper();
        }
    }