Symfony closure compiler pass

ClosureCompilerPass.php

<?php

namespace DependencyInjection\Compiler;

use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
use Symfony\Component\DependencyInjection\ContainerBuilder;

class ClosureCompilerPass implements CompilerPassInterface
{
    private $pass;

    public function __construct($pass)
    {
        $this->pass = $pass;
    }

    public function process(ContainerBuilder $container)
    {
        call_user_func($this->pass, $container);
    }
}

SomeBundle.php

<?php

namespace SomeBundle;

use DependencyInjection\Compiler\ClosureCompilerPass;
use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\DependencyInjection\Reference;
use Symfony\Component\HttpKernel\Bundle\Bundle;

class SomeBundle extends Bundle
{
    public function build(ContainerBuilder $container)
    {
        parent::build($container);

        $container->addCompilerPass(new ClosureCompilerPass(function (ContainerBuilder $container) {
            // example from http://symfony.com/doc/current/components/dependency_injection/tags.html
            if (!$container->hasDefinition('acme_mailer.transport_chain')) {
                return;
            }

            $definition = $container->getDefinition(
                'acme_mailer.transport_chain'
            );

            $taggedServices = $container->findTaggedServiceIds(
                'acme_mailer.transport'
            );
            foreach ($taggedServices as $id => $tags) {
                foreach ($tags as $attributes) {
                    $definition->addMethodCall(
                        'addTransport',
                        array(new Reference($id), $attributes["alias"])
                    );
                }
            }
        }));
    }
}