用户登录＆amp;注册问题

Question

尝试设置登录和注册控制器，但我一直得到相同的错误，所有在线解决方案都没有帮助。错误出现在行上：＆＃34; displayMyAlertMessage＆＃34;和UserDefaults。

 @IBAction func signUpButton(_ sender: Any) {

    let userName = userFirstName.text;
    let userLast = userLastName.text;

    if(userName!.isEmpty || userLast!.isEmpty)
    {
        displayMYAlertMessage("All Fields are RequireD");

        return;
    }
    // Store data
        UserDefaults.standardUserDefaults().setObject("userName", forKey: "userName")
        UserDefaults.standardUserDefaults().setObject("userLast", forKey: "userLast")

        let userName = UserDefaults.standardUserDefaults().stringForKey("userName")
        let userLast = UserDefaults.standardUserDefaults().stringForKey("userLast")



        // Display alert message with confirmation.
        var myAlert = UIAlertController(title:"Alert", message:"Registration is successful. Thank you!", preferredStyle: UIAlertControllerStyle.alert);

        let okAction = UIAlertAction(title:"Ok", style:UIAlertActionStyle.default){ action in
            self.dismiss(animated: true, completion:nil);
        }

        myAlert.addAction(okAction);
        self.present(myAlert, animated:true, completion:nil);

    }

    }