code: public function process(ContainerBuilder $container)
      {
          $definition = $container->findDefinition(ServiceCollection::class);
          $services = $container->findTaggedServiceIds('ds_api.service');
  
          foreach ($services as $id => $tags) {
              foreach ($tags as $tag) {
                  if (array_key_exists('alias', $tag)) {
                      $definition->addMethodCall('set', [ $tag['alias'], new Reference($id) ]);
                  } else {
                      $definition->addMethodCall('add', [ new Reference($id) ]);
                  }
              }
          }
      }
docs: Process
  
  @param \Symfony\Component\DependencyInjection\ContainerBuilder $container