code: def create_sitemap(app, exception):
      
      site_url = app.builder.config.site_url or app.builder.config.html_baseurl
      if not site_url:
          print("sphinx-sitemap error: neither html_baseurl nor site_url "
                "are set in conf.py. Sitemap not built.")
          return
      if (not app.sitemap_links):
          print("sphinx-sitemap warning: No pages generated for sitemap.xml")
          return
  
      ET.register_namespace('xhtml', "http://www.w3.org/1999/xhtml")
  
      root = ET.Element("urlset")
      root.set("xmlns", "http://www.sitemaps.org/schemas/sitemap/0.9")
  
      get_locales(app, exception)
  
      if app.builder.config.version:
          version = app.builder.config.version + '/'
      else:
          version = app.builder.config.version
  
      for link in app.sitemap_links:
          url = ET.SubElement(root, "url")
          if app.builder.config.language is not None:
              ET.SubElement(url, "loc").text = site_url + \
                    app.builder.config.language + '/' + version + link
              if len(app.locales) > 0:
                  for lang in app.locales:
                      linktag = ET.SubElement(
                          url,
                          "{http://www.w3.org/1999/xhtml}link"
                      )
                      linktag.set("rel", "alternate")
                      linktag.set("hreflang", lang)
                      linktag.set("href", site_url + lang + '/' + version + link)
          elif app.builder.config.version:
              ET.SubElement(url, "loc").text = site_url + version + link
          else:
              ET.SubElement(url, "loc").text = site_url + link
  
      filename = app.outdir + "/sitemap.xml"
      ET.ElementTree(root).write(filename,
                                 xml_declaration=True,
                                 encoding='utf-8',
                                 method="xml")
      print("sitemap.xml was generated for URL %s in %s" % (site_url, filename))
docs: Generates the sitemap.xml from the collected HTML page links