code: def toMessage(self, message=None):
          
          if message is None:
              warnings.warn('Passing None to Extension.toMessage is deprecated. '
                            'Creating a message assuming you want OpenID 2.',
                            DeprecationWarning, stacklevel=2)
              message = message_module.Message(message_module.OPENID2_NS)
  
          implicit = message.isOpenID1()
  
          try:
              message.namespaces.addAlias(self.ns_uri, self.ns_alias,
                                          implicit=implicit)
          except KeyError:
              if message.namespaces.getAlias(self.ns_uri) != self.ns_alias:
                  raise
  
          message.updateArgs(self.ns_uri, self.getExtensionArgs())
          return message
docs: Add the arguments from this extension to the provided
          message, or create a new message containing only those
          arguments.
  
          @returns: The message with the extension arguments added