/**
  * {@inheritdoc}
  */
 protected function getAddFormRoute(EntityTypeInterface $entity_type)
 {
     if ($route = parent::getAddFormRoute($entity_type)) {
         $route->setOption('_admin_route', TRUE);
         return $route;
     }
 }
 public function getAddFormRoute(EntityTypeInterface $entity_type)
 {
     return parent::getAddFormRoute($entity_type);
 }