/**
  * @param $hash
  * @param $teaser
  * @return null|Aggregation
  */
 public function findOrCreateByHash($hash, $teaser)
 {
     /**
      * @var Aggregation $aggregation
      */
     $aggregation = $this->source->findByHash($hash);
     if (empty($aggregation)) {
         $aggregation = $this->source->create(['exception_hash' => $hash, 'exception_teaser' => $teaser]);
         $this->source->save($aggregation);
     }
     return $aggregation;
 }