docs: def render(self):
          """Render reply from Python object to XML string"""
          tpl = '<xml>\n{data}\n</xml>'
          nodes = []
          msg_type = '<MsgType><![CDATA[{msg_type}]]></MsgType>'.format(
              msg_type=self.type
          )
          nodes.append(msg_type)
          for name, field in self._fields.items():
              value = getattr(self, name, field.default)
              node_xml = field.to_xml(value)
              nodes.append(node_xml)
          data = '\n'.join(nodes)
          return tpl.format(data=data)