Как получить доступ к текущей громкости iPhone и отобразить ее в своем приложении на swift?

let audioFiles: [String: String] = [
        "": "",
        "": "",
        "": "",
        "":"",
        ]
    
    var players : [AVAudioPlayer] = []
    var volume = 0.0
    
//    init () {
//        for (name, ext) in audioFiles {
//            let a1 = setupAudioPlayerWithFile(file: name as NSString, type:ext as NSString)
//            players.append(a1!)
//        }
//    }
//
//    required init?(coder aDecoder: NSCoder) {
//        fatalError("init(coder:) has not been implemented")
//    }
    
    func setVolume(v:Double) {
        volume = v
        for audioPlayer in players {
            audioPlayer.volume = Float(volume)
        }
    }
    
    func playSound(i:Int)
    {
        let audioPlayer = players[i]
        audioPlayer.play()
    }
    
    func setupAudioPlayerWithFile(file:NSString, type:NSString) -> AVAudioPlayer?  {
        let path = Bundle.main.path(forResource: file as String, ofType: type as String)
        let url = NSURL.fileURL(withPath: path!)
        var audioPlayer:AVAudioPlayer?
        do {
            try audioPlayer = AVAudioPlayer(contentsOf: url)
            audioPlayer!.prepareToPlay()
            
        } catch {
            print("Player not available")
        }
        return audioPlayer
    }

do {
    try AVAudioSession.sharedInstance().setActive(true, options: [])
} catch {
    print(error)
}

Timer.scheduledTimer(withTimeInterval: 0.2, repeats: true) {(timer) in
    print(AVAudioSession.sharedInstance().outputVolume)
}