code: public function prepend(ContainerBuilder $container): void
      {
          $configDir = $container->getParameter('kernel.project_dir').'/app/config';
  
          if (file_exists($configDir.'/parameters.yml') || !file_exists($configDir.'/parameters.yml.dist')) {
              return;
          }
  
          $loader = new YamlFileLoader(
              $container,
              new FileLocator($configDir)
          );
  
          $loader->load('parameters.yml.dist');
      }
docs: {@inheritdoc}