docs: function processEntry(entry, siteConfig) {
      const returnArr = [siteConfig.spacing + '<url>'];
  
      const loc = entry.getLoc ? entry.getLoc(siteConfig.siteUrl, entry.loc, entry) : entry.loc;
      returnArr.push(siteConfig.spacing + siteConfig.spacing + wrapTag('loc', loc));
  
      let lastmod = entry.lastmod;
      if (lastmod) {
          //format mtime to ISO (same as +00:00)
          lastmod = new Date(lastmod).toISOString();
          returnArr.push(siteConfig.spacing + siteConfig.spacing + wrapTag('lastmod', lastmod));
      }
  
      const changefreq = entry.changefreq;
      if (changefreq) {
          returnArr.push(siteConfig.spacing + siteConfig.spacing + wrapTag('changefreq', changefreq));
      }
  
      let priority;
  
      if (typeof entry.priority === 'function') {
          priority = entry.priority(siteConfig.siteUrl, entry.loc, entry);
      } else if (typeof entry.priority !== 'undefined') {
          priority = entry.priority;
      }
      if (typeof priority !== 'undefined') {
          returnArr.push(siteConfig.spacing + siteConfig.spacing + wrapTag('priority', priority));
      }
  
      const hreflang = entry.hreflang;
      if (hreflang && hreflang.length > 0) {
          const file = entry.file;
          hreflang.forEach(function(item) {
              const href = item.getHref(siteConfig.siteUrl, file, item.lang, loc);
              const tag = '<xhtml:link rel="alternate" hreflang="' + item.lang + '" href="' + href + '" />';
              returnArr.push(siteConfig.spacing + siteConfig.spacing + tag);
          });
      }
  
      returnArr.push(siteConfig.spacing + '</url>');
      return returnArr.join(siteConfig.newLine);
  }