code: def __create_url_node_for_content(self, content, content_type, url=None, modification_time=None):
          
          loc = url
          if loc is None:
              loc = urljoin(self.url_site, self.context.get('ARTICLE_URL').format(**content.url_format))
          lastmod = None
          if modification_time is not None:
              lastmod = modification_time.strftime('%Y-%m-%d')
          else:
              if content is not None:
                  if getattr(content, 'modified', None) is not None:
                      lastmod = getattr(content, 'modified').strftime('%Y-%m-%d')
                  elif getattr(content, 'date', None) is not None:
                      lastmod = getattr(content, 'date').strftime('%Y-%m-%d')
  
          output = "<loc>{}</loc>".format(loc)
          if lastmod is not None:
              output += "\n<lastmod>{}</lastmod>".format(lastmod)
          output += "\n<changefreq>{}</changefreq>".format(self.settings.get('changefrequencies').get(content_type))
          output += "\n<priority>{:.2f}</priority>".format(self.settings.get('priorities').get(content_type))
  
          return self.template_url.format(output)
docs: Creates the required <url> node for the sitemap xml.
          :param content: the content class to handle
          :type content: pelican.contents.Content | None
          :param content_type: the type of the given content to match settings.EXTENDED_SITEMAP_PLUGIN
          :type content_type; str
          :param url; if given, the URL to use instead of the url of the content instance
          :type url: str
          :param modification_time: the modification time of the url, will be used instead of content date if given
          :type modification_time: datetime.datetime | None
          :returns: the text node
          :rtype: str