public MembershipPayment(PaymentBase nextHandler, PaymentRequest requestObj) : base(nextHandler, requestObj)
 {
 }
 public PhysicalProductPayment(PaymentBase nextHandler, PaymentRequest requestObj) : base(nextHandler, requestObj)
 {
 }
 public BookPayment(PaymentBase nextHandler, PaymentRequest requestObj) : base(nextHandler, requestObj)
 {
 }
 public PaymentBase(PaymentBase nextHandler, PaymentRequest requestObj)
 {
     NextPaymentType = nextHandler;
     RequestObj      = requestObj;
 }