protected function getContentTagsList()
    {
        $ret = [];

        if (!$this->labelManager) {
            return;
        }

        $tagList = $this->labelManager->loadAllLabels();

        if ($tagList) {
            foreach ($tagList as $tag) {
                $ret[$tag->tid] = $tag->name;
            }
        }

        return $ret;
    }