public function onPostSerialize(ObjectEvent $event)
    {
        $visitor = $event->getVisitor();
        $document = $event->getObject();

        if (!$document instanceof ParentBehavior || !$document->getParent() instanceof UuidBehavior) {
            return;
        }

        $visitor->addData('parentUuid', $document->getParent()->getUuid());
    }