public static void Test()
        {
            var turnstile = new Turnstile();

            turnstile.Enter();
            turnstile.Pay();
        }
 public OpenTurnstileState(Turnstile turnstile)
 {
     Turnstile = turnstile;
 }
 public ProcessingTurnstileState(Turnstile turnstile)
 {
     Turnstile = turnstile;
 }
 public ClosedTurnstileState(Turnstile turnstile)
 {
     Turnstile = turnstile;
 }