code: function(userId, messageId, callback) {
        if (!userId) return callback(new Error(utils.i18n.messages.userId));
        messageId = utils.toUUID(messageId);
        if (!messageId) return callback(new Error(utils.i18n.messages.mid));
        utils.debug('Message getFromUser: ' + userId + ', ' + messageId);
  
        request.get({
          path: '/users/' + querystring.escape(userId) + '/messages/' + messageId
        }, callback);
      }
docs: Retrieve a message in a conversation from a user
  
  @param  {String}   userId          User ID
  @param  {String}   messageId       Message ID
  @param  {Function} callback        Callback function