protected function getPageChangeFrequency(array $page)
    {
        $ret = 0;

        if (!empty($page['tx_metaseo_change_frequency'])) {
            $ret = (int)$page['tx_metaseo_change_frequency'];
        } elseif (!empty($this->conf['sitemap.']['changeFrequency'])) {
            $ret = (int)$this->conf['sitemap.']['changeFrequency'];
        }

        if (empty($pageChangeFrequency)) {
            $ret = 0;
        }

        return $ret;
    }