/**
  * Content plugins callback.
  *
  * @param ContentEvent $event
  */
 public function onContentPlugins(ContentEvent $event)
 {
     if (!$event['markdown']) {
         return;
     }
     $content = $event->getContent();
     $content = App::markdown()->parse($content, is_array($event['markdown']) ? $event['markdown'] : []);
     $event->setContent($content);
 }