public function updateKeywordLinks(AbstractClassContent $content, $keywords, BBUserToken $token = null)
    {
        if (!is_array($keywords)) {
            $keywords = [$keywords];
        }

        foreach ($keywords as $keyword) {
            if (!($keyword instanceof Keyword)) {
                continue;
            }

            if (
                null !== $token &&
                null !== $draft = $this->_em->getRepository('BackBee\ClassContent\Revision')->getDraft($keyword, $token)
            ) {
                $keyword->setDraft($draft);
            }

            if (
                empty($keyword->value)
                || (null === $realKeyword = $this->_em->find('BackBee\NestedNode\KeyWord', $keyword->value))
            ) {
                continue;
            }

            if (!$realKeyword->getContent()->contains($content)) {
                $realKeyword->getContent()->add($content);
            }
        }
    }