push notification with swift

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.
        let notificationTypes: UIUserNotificationType = [UIUserNotificationType.alert, UIUserNotificationType.badge, UIUserNotificationType.sound]
        let pushNotificationSettings = UIUserNotificationSettings(types: notificationTypes, categories: nil)
        application.registerUserNotificationSettings(pushNotificationSettings)
        application.registerForRemoteNotifications()
        return true
    }
    
    func application(_: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
        let   tokenString = deviceToken.reduce("", {$0 + String(format: "%02X",    $1)})
        print("deviceToken: \(tokenString)")
    }

    func application(_ application: UIApplication, didFailToRegisterForRemoteNotificationsWithError error: Error) {
        print(error)
    }
    
    private func application(application: UIApplication, didReceiveRemoteNotification userInfo: [NSObject : AnyObject]) {
        print(userInfo)
    }