Not getting value change using UISlider.observer

Question

I am attempting to detect changes of a UISlider value using the observer option but I am not getting any output. Selected parts of code here

class MainViewController: UIViewController {
    @IBOutlet weak var speedSlider: UISlider!

    var speedSliderObserver:  NSKeyValueObservation?

    override func viewDidLoad() { super.viewDidLoad()  setSettings()   }

    func setSettings() {
        speedSliderObserver = speedSlider.observe(.value, options: [.old, .new]) { object, change in 
print("speedSlider from: (change.oldValue!), to: (change.newValue!)")         
    } 
}

Am I using observe correctly or is there some other way?