code: def log_url (self, url_data, priority=None):
          
          self.xml_starttag(u'url')
          self.xml_tag(u'loc', url_data.url)
          if url_data.modified:
              self.xml_tag(u'lastmod', self.format_modified(url_data.modified, sep="T"))
          self.xml_tag(u'changefreq', self.frequency)
          self.xml_tag(u'priority', "%.2f" % priority)
          self.xml_endtag(u'url')
          self.flush()
docs: Log URL data in sitemap format.