public static function getObjectTag($class, $id)
    {
        if (is_object($class) && $class instanceof ActiveRecord) {
            $class = $class->className();
        } elseif (!is_string($class)) {
            throw new InvalidParamException('Param $class must be a string or an object.');
        }
        return $class . '[ObjectTag:' . self::getCacheKeyById($id) . ']';
    }