public function getBlockTypes()
    {
        $result = [];
        $app = Application::getFacadeApplication();
        $db = $app->make(Connection::class);
        $rs = $db->executeQuery('select btID from BlockTypeSetBlockTypes where btsID = ? order by displayOrder asc', [$this->getBlockTypeSetID()]);
        while (($btID = $rs->fetchColumn()) !== false) {
            $bt = BlockType::getByID($btID);
            if ($bt !== null) {
                $result[] = $bt;
            }
        }

        return $result;
    }