code: public function load(array $config, ContainerBuilder $container)
      {
          $container->register('session', 'Symfony\Component\HttpFoundation\Session\Session');
  
          $container->register('session.session_subscriber', 'Nice\Session\SessionSubscriber')
              ->addArgument(new Reference('service_container'))
              ->addTag('kernel.event_subscriber');
      }
docs: Loads a specific configuration.
  
  @param array            $config    An array of configuration values
  @param ContainerBuilder $container A ContainerBuilder instance