public function addTitleOnPostSerialize(ObjectEvent $event)
    {
        $articlePage = $event->getObject();
        $visitor = $event->getVisitor();
        $context = $event->getContext();

        if (!$articlePage instanceof ArticlePageDocument) {
            return;
        }

        $visitor->addData('title', $context->accept($articlePage->getParent()->getTitle()));
    }