/**
  * Form event - adds entities to uow to be delete
  * 
  * @param DataEvent $event
  */
 public function postBind(DataEvent $event)
 {
     $collection = $event->getData();
     if ($collection instanceof PersistentCollection) {
         foreach ($collection->getDeleteDiff() as $entity) {
             $this->om->remove($entity);
         }
     }
 }