Исправь этот код, чтобы он стал примером паттерна Хранитель (Memento)
class Audioplayer
    {
        public double Position { get; set; }
        private bool playing = false;
        public string path { get; set; }
        public void Play(double? position)
        {
            if (path != null)
            {
                playing = true;
                if (position.HasValue)
                {
                 //playfromposition
                }
                else
                {
                    //playfromthis.position
                }
            }
           
        }
        public void Pause()
        {
            playing = false;
            //playerpause
        }
        public Point CloseApp()
        {
            return new Point(Position, path);
        }
        public void GetLastPlayed(Point point)
        {
            this.Position = point.Seconds;
            this.path = point.Path;
        }
    }

    class LastPlayed
    {
        public Point point { get; set; }
        public LastPlayed()
        {
            point = new Point();
        }
    }

    public class Point
    {
        public double Seconds { get; private set; }
        public string Path { get; private set; }

        public Point(double seconds, string path)
        {
            this.Seconds = seconds;
            this.Path = path;
        }
    }