 	/// Observe changes in volume.
 	///
 	/// This method is called when the user presses either of the volume buttons.
-	public func observeValue(forKeyPath keyPath: String?, of object: AnyObject?, change: [NSKeyValueChangeKey : AnyObject]?, context: UnsafeMutableRawPointer) {
+	public override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey: Any]?, context: UnsafeMutableRawPointer?) {
 		// Exit early if the object isn't an `AVAudioSession`.
 		guard object is AVAudioSession else { return }
 		
 		show()
 	}
-	
 	
 	/// Observe when the application background state changes.
 	public func applicationWillResignActive(notification: Notification) {

			
			// Stop observing application changes and device rotation
			NotificationCenter.default.removeObserver(self)
		}
	}
	

	/// A `UIWindow` that is inserted above the system status bar to show the volume indicator.
	internal let volumeWindow: UIWindow = UIWindow()
	
	/// A standard iOS `MPVolumeView` that never appears but is necessary to hide the system volume HUD.
	private let volumeView = MPVolumeView()
	
	/// A timer that controls when the `VolumeBar` automatically hides.
	///
	/// Each time a volume button is pressed, the timer is invalidated and set again with duration `minimumVisibleDuration`.
