public function getCopyCount(ContainerInterface $container)
    {
        $query = $this->getEntityManager()->createQuery(
            "SELECT COUNT(c.id) FROM {$this->getClassName()} c WHERE c.copy = :copied"
        );

        /** @noinspection PhpIncompatibleReturnTypeInspection */
        return $query
            ->setParameter('copied', $container)
            ->getSingleResult(Query::HYDRATE_SINGLE_SCALAR);
    }