public function find(ReturnNumber $returnNumber)
 {
     return ProductReturn::fromEvents(array_map(function (StoredEvent $storedEvent) {
         return $storedEvent->getEvent();
     }, $this->registry->getRepository(StoredEvent::class)->findByAggregateId($returnNumber->toString())));
 }
 public function delete(ReturnNumber $returnNumber)
 {
     $outstanding = $this->registry->getRepository(OutstandingReturn::class)->find($returnNumber->toString());
     $this->registry->getManager()->remove($outstanding);
     $this->registry->getManager()->flush();
 }