code: public function handle(CreateMetaModelEvent $event)
      {
          if (null === $metaModel = $event->getMetaModel()) {
              return;
          }
  
          foreach ($this->attributeFactory->createAttributesForMetaModel($metaModel) as $attribute) {
              $metaModel->addAttribute($attribute);
          }
      }
docs: Add attributes to the MetaModel.
  
  @param CreateMetaModelEvent $event The event.
  
  @return void