public PaymentRequest PaymentRequest(int n)
            {
                if (n >= 0 && n <= 9)
                {
                    PaymentRequest request;

                    if (!paymentRequest.TryGetValue(n, out request))
                    {
                        request = new PaymentRequest(this, n);
                        request.CurrencyCode = this.CurrencyCode;

                        paymentRequest[n] = request;
                    }

                    return request;
                }
                else
                {
                    throw new ArgumentOutOfRangeException();
                }
            }
 public Item(PaymentRequest r, int n, int m)
 {
     this.m = m;
     this.n = n;
     this.r = r;
 }