Symfony\Component\DependencyInjection\Dumper\XmlDumper::addServiceAlias PHP Method

    private function addServiceAlias($alias, $id, \DOMElement $parent)
    {
        $service = $this->document->createElement('service');
        $service->setAttribute('id', $alias);
        $service->setAttribute('alias', $id);
        if (!$id->isPublic()) {
            $service->setAttribute('public', 'false');
        }
        $parent->appendChild($service);
    }