private function getPageTitle(ArticleInterface $document)
    {
        $pageTitleProperty = $this->getPageTitleProperty($document);
        if (!$pageTitleProperty) {
            return;
        }

        $stagedData = $document->getStructure()->getStagedData();
        if (array_key_exists($pageTitleProperty->getName(), $stagedData)) {
            return $stagedData[$pageTitleProperty->getName()];
        }

        if (!$document->getStructure()->hasProperty($pageTitleProperty->getName())) {
            return;
        }

        return $document->getStructure()->getProperty($pageTitleProperty->getName())->getValue();
    }