Goetas\Twital\EventSubscriber\CustomNamespaceSubscriber::addCustomNamespace PHP Method

    public function addCustomNamespace(TemplateEvent $event)
    {
        foreach (iterator_to_array($event->getTemplate()->getDocument()->childNodes) as $child) {
            if ($child instanceof \DOMElement) {
                DOMHelper::checkNamespaces($child, $this->customNamespaces);
            }
        }
    }