public function delete($ids, \DatabaseTransaction $transaction = NULL)
 {
     $transaction = isset($transaction) ? $transaction : db_transaction();
     try {
         parent::delete($ids, $transaction);
         db_delete('observers')->condition('observable_id', $ids, 'IN')->execute();
     } catch (\Exception $e) {
         watchdog_exception($this->entityType, $e);
         $transaction->rollback();
         throw $e;
     }
 }
 /**
  * {@inheritdoc}
  */
 public function delete($ids, \DatabaseTransaction $transaction = NULL)
 {
     if ($this->isFastDeleteEnabled()) {
         $this->fastDelete($ids, $transaction);
         return;
     }
     parent::delete($ids, $transaction);
 }