/**
  * @param bool $id
  * @throws NotFoundHttpException
  * @return AuthItemChild
  */
 protected function findModel($id = false)
 {
     if (!$id) {
         $model = new AuthItemChild();
     } else {
         if (!($model = AuthItemChild::findOne($id))) {
             throw new NotFoundHttpException('Model not found.');
         }
     }
     return $model;
 }