/**
  * @param ServiceLocatorInterface $serviceLocator
  * @return UserService
  */
 public function createService(ServiceLocatorInterface $serviceLocator)
 {
     $service = new UserService();
     /** @var EntityManager $em */
     $em = $serviceLocator->get(EntityManager::class);
     $service->setEntityManager($em);
     return $service;
 }