public function findAllForNotifiable($notifiable_identifier, $notifiable_class, $order = 'DESC')
    {
        return $this->createQueryBuilder('nn')
            ->join('nn.notifiableEntity', 'ne')
            ->join('nn.notification', 'no')
            ->where('ne.identifier = :identifier')
            ->andWhere('ne.class = :class')
            ->setParameter('identifier', $notifiable_identifier)
            ->setParameter('class', $notifiable_class)
            ->orderBy('no.id', $order)
            ->getQuery()
            ->getResult()
        ;
    }