/**
  * @param form_persistentdocument_form $document
  * @return void
  */
 protected function preDelete($document)
 {
     parent::preDelete($document);
     if ($document->getResponseCount()) {
         $responses = $this->pp->createQuery('modules_form/response')->add(Restrictions::eq('parentForm.id', $document->getId()))->find();
         foreach ($responses as $response) {
             $response->delete();
         }
     }
 }