类型“ ViewController”的值没有成员“ authUI”？

Question

我是iOS开发的新手。我想实现Firebase不礼貌的用户界面

这是我的 ViewController 文件

import UIKit
import Firebase
import FirebaseCore
import FirebaseAuth
import FirebaseUI
import FirebaseFirestore

class ViewController: UIViewController{
    //let authUI = FUIAuth.defaultAuthUI()
    //let authui = FirebaseApp.configure()

    override func viewDidLoad() {
        super.viewDidLoad()
         // FirebaseApp.configure()
        if FirebaseApp.app() == nil {
            FirebaseApp.configure()
        }
        print("came inside viewdialoadds")
       //  logiin()
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
         print("came inside parttwoooooooooooo")
    }

    @IBAction func loginfunction(_: UIButton) {
         print("Tappeddddddddddddddddddddd")
          logiin()
    }

    func logiin() {
        print("login called")
        if FirebaseApp.app() == nil {
             print("login called firebase now confieeddd")
            FirebaseApp.configure()
        }
       // FirebaseApp.configure()
        print("login called firebase UI  confieeddd")
        let authUI = FUIAuth.defaultAuthUI()
        // You need to adopt a FUIAuthDelegate protocol to receive callback
        authUI?.delegate = self as? FUIAuthDelegate
       // authUI.delegate = self

        let providers: [FUIAuthProvider] = [
            FUIGoogleAuth(),
            FUIPhoneAuth(authUI:FUIAuth.defaultAuthUI()!),
            ]
        self.authUI.providers = providers

        func application(_ app: UIApplication, open url: URL,
                         options: [UIApplicationOpenURLOptionsKey : Any]) -> Bool {
            let sourceApplication = options[UIApplicationOpenURLOptionsKey.sourceApplication] as! String?
            if FUIAuth.defaultAuthUI()?.handleOpen(url, sourceApplication: sourceApplication) ?? false {
                return true
            }
            // other URL handling goes here.
            return false
        }

    }

我遇到编译时错误，请在下面添加屏幕截图，请查看

任何人都请指定我的代码有什么问题。...我在https://firebase.google.com/docs/auth/ios/firebaseui?authuser=0此处找到了文档