private function getUserAuthClass()
    {
        if ($this instanceof UserBehaviorInterface) {
            $class = $this->userAuthClass();
            
            if (!$class) { // return false;
                return false;
            }
            
            if (!is_object($class)) {
                return Yii::createObject($class);
            }
    
            return $class;
        }
        
        return false;
    }