public function get_assistants() {

		global $wpdb;
		$results = $wpdb->get_col(
			$wpdb->prepare(
				"SELECT user_id FROM {$wpdb->usermeta}
			 WHERE meta_key = 'llms_parent_instructors'
			   AND meta_value LIKE %s;",
				'%i:' . $this->get_id() . ';%'
			)
		); // db call ok; no-cache ok.

		return $results;

	}