code: def toFormMarkup(self,
                       action_url,
                       form_tag_attrs=None,
                       submit_text="Continue"):
          
          if ElementTree is None:
              raise RuntimeError('This function requires ElementTree.')
  
          assert action_url is not None
  
          form = ElementTree.Element('form')
  
          if form_tag_attrs:
              for name, attr in form_tag_attrs.items():
                  form.attrib[name] = attr
  
          form.attrib['action'] = oidutil.toUnicode(action_url)
          form.attrib['method'] = 'post'
          form.attrib['accept-charset'] = 'UTF-8'
          form.attrib['enctype'] = 'application/x-www-form-urlencoded'
  
          for name, value in self.toPostArgs().items():
              attrs = {
                  'type': 'hidden',
                  'name': oidutil.toUnicode(name),
                  'value': oidutil.toUnicode(value)
              }
              form.append(ElementTree.Element('input', attrs))
  
          submit = ElementTree.Element(
              'input',
              {'type': 'submit',
               'value': oidutil.toUnicode(submit_text)})
          form.append(submit)
  
          return str(ElementTree.tostring(form, encoding='utf-8'),
                     encoding="utf-8")
docs: Generate HTML form markup that contains the values in this
          message, to be HTTP POSTed as x-www-form-urlencoded UTF-8.
  
          @param action_url: The URL to which the form will be POSTed
          @type action_url: str
  
          @param form_tag_attrs: Dictionary of attributes to be added to
              the form tag. 'accept-charset' and 'enctype' have defaults
              that can be overridden. If a value is supplied for
              'action' or 'method', it will be replaced.
          @type form_tag_attrs: {unicode: unicode}
  
          @param submit_text: The text that will appear on the submit
              button for this form.
          @type submit_text: unicode
  
          @returns: A string containing (X)HTML markup for a form that
              encodes the values in this Message object.
          @rtype: str