code: def update(self, body):
          
          data = values.of({'Body': body, })
  
          payload = self._version.update(
              'POST',
              self._uri,
              data=data,
          )
  
          return MessageInstance(
              self._version,
              payload,
              account_sid=self._solution['account_sid'],
              sid=self._solution['sid'],
          )
docs: Update the MessageInstance
  
          :param unicode body: The text of the message you want to send
  
          :returns: Updated MessageInstance
          :rtype: twilio.rest.api.v2010.account.message.MessageInstance