public function serializeContentObjectAttribute($package, $objectAttribute)
    {
        $node = $this->createContentObjectAttributeDOMNode($objectAttribute);

        $value = $objectAttribute->content();
        $value = $value instanceof Value ? $value : $this->fieldType->getEmptyValue();

        $xml = clone $value->xml;

        $this->transformLinksToRemoteLinks($xml);

        $dom = $node->ownerDocument;

        $valueNode = $dom->createElement('rich-text-xml');
        $valueNode->appendChild($dom->createTextNode($xml->saveXML()));
        $node->appendChild($valueNode);

        return $node;
    }