code: def update(self, author=values.unset, attributes=values.unset,
                 date_created=values.unset, date_updated=values.unset,
                 body=values.unset):
          
          return self._proxy.update(
              author=author,
              attributes=attributes,
              date_created=date_created,
              date_updated=date_updated,
              body=body,
          )
docs: Update the MessageInstance
  
          :param unicode author: The identity of the message's author.
          :param unicode attributes: A string metadata field you can use to store any data you wish.
          :param datetime date_created: The date that this resource was created.
          :param datetime date_updated: The date that this resource was last updated.
          :param unicode body: The contents of the message.
  
          :returns: Updated MessageInstance
          :rtype: twilio.rest.messaging.v1.session.message.MessageInstance