putResultDataBody(dataMap, fessConfig.getIndexFieldExpires(), documentExpires);
        }
        // lang
        final String lang = systemHelper.normalizeHtmlLang(
                getSingleNodeValue(document, getLangXpath(fessConfig, xpathConfigMap), node -> pruneNode(node, crawlingConfig)));
        if (lang != null) {
            putResultDataBody(dataMap, fessConfig.getIndexFieldLang(), lang);
        }
        // title