/**
  * @param AssetCollection $assetCollection
  * @return void
  */
 public function deleteAssetCollectionAction(AssetCollection $assetCollection)
 {
     foreach ($this->siteRepository->findByAssetCollection($assetCollection) as $site) {
         $site->setAssetCollection(null);
         $this->siteRepository->update($site);
     }
     parent::deleteAssetCollectionAction($assetCollection);
 }