public function contains($bt)
    {
        $result = false;
        $btID = (int) (is_object($bt) ? $bt->getBlockTypeID() : $bt);
        if ($btID !== 0) {
            $app = Application::getFacadeApplication();
            $db = $app->make(Connection::class);
            $result = $db->fetchColumn('select btID from BlockTypeSetBlockTypes where btsID = ? and btID = ?', [$this->getBlockTypeSetID(), $btID]) !== false;
        }

        return $result;
    }