code: public function create(ContainerBuilder $container, $contextName, array $config)
      {
          if (false == class_exists('\Eki\Payum\Nganluong\PaymentFactory')) {
              throw new RuntimeException('Cannot find nganluong payment factory class');
          }
  
          $loader = new XmlFileLoader($container, new FileLocator(__DIR__.'/Resources/config'));
          $loader->load('nganluong.xml');
  		
          return parent::create($container, $contextName, $config);
      }
docs: {@inheritdoc}