public function verifyAlias($alias, $langId)
    {
        if (Yii::$app->hasModule($alias) && $this->parent_nav_id == 0) {
            $this->addError('alias', Module::t('nav_item_model_error_modulenameexists', ['alias' => $alias]));

            return false;
        }

        if ($this->parent_nav_id === null) {
            $this->addError('parent_nav_id', Module::t('nav_item_model_error_parentnavidcannotnull'));
            
            return false;
        }

        if ($this->find()->where(['alias' => $alias, 'lang_id' => $langId])->leftJoin('cms_nav', 'cms_nav_item.nav_id=cms_nav.id')->andWhere(['=', 'cms_nav.parent_nav_id', $this->parent_nav_id])->exists()) {
            $this->addError('alias', Module::t('nav_item_model_error_urlsegementexistsalready'));

            return false;
        }
    }