public function preSetData(FormEvent $event)
    {
        $entity = $event->getData();
    
        if ($entity instanceof FileInterface && null !== $entity->getId()){
            try {
                $this->fileManager->copyFileToTemporaryDirectory($entity);
            } catch (\Gaufrette\Exception\FileNotFound $e) {
                $event->setData(null);
            }
        }
    }