How to put a provider controller inside a provider controller?

Question

PHP

There is a provider class SystemControllerProvider, in which another controller provider AdminGroupsControllerProvider should be connected.
In this example, the white page response code is 200, and the rest of the routes do not work either

class SystemControllerProvider implements ControllerProviderInterface
{
    public function connect(Application $app)
    {
        $controllers = $app['controllers_factory'];

        $controllers->mount('/groups', new AdminGroupsControllerProvider());

        return $controllers;
    }
}

class AdminGroupsControllerProvider implements ControllerProviderInterface {

  public function connect(Application $app) {

        $controllers = $app['controllers_factory'];

        $controllers->get('/', "Controllers\AdminGroupsControllerProvider::getGroups");

        return $controllers;
    }

public function getGroups(Request $request, Application $app){

    $data = [
      "name" => 'Тест',
      "perm" => [1,2,3,4,5,6],
      "addedby" =>$app['session']->get('uid')	
    ];

    $responseStatus = 200;

    $response = new JsonResponse();
                $response->headers->set('Content-Type', 'application/json');
               $response->setEncodingOptions(JSON_UNESCAPED_UNICODE);
               $response->setStatusCode(200);
               $response->setData($data);
               return $response;
  }
}