I have the following code:

```
class firstVC: UIViewController {
    var timer : Timer?

    func scheduledTimerWithTimeInterval(){
        timer = Timer.scheduledTimer(timeInterval: 60, target: self, 
        selector: #selector(self.anotherFunc), userInfo: nil, repeats: 
        true)
    }

    override func viewDidAppear(_ animated: Bool) {
        scheduledTimerWithTimeInterval()
    }
}

```

I'm trying to stop the timer without success:

```
func stopTimer() {
    if timer != nil {
        timer?.invalidate()
        timer = nil
    }
}

override func viewDidDisappear(_ animated: Bool) {
    super.viewDidDisappear(animated)
    stopTimer()
}

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    stopTimer()
}

```

I even tried to put the stop function in `applicationWillResignActive`
And in `applicationDidEnterBackground` but it didn't stop:

```
firstVC().stopTimer()

```

Your help will be appreciated, thank you.