code: public function handle(GetPropertyOptionsEvent $event)
      {
          if (!$this->wantToHandle($event) || ($event->getPropertyName() !== 'template')) {
              return;
          }
  
          $event->setOptions($this->templateList->getTemplatesForBase('metamodel_'));
      }
docs: Retrieve the options for the attributes.
  
  @param GetPropertyOptionsEvent $event The event.
  
  @return void