1.) Declare contract Class 2 variales List customerList; str customer; [DataMemberAttribute('customer'), SysOperationLabelAttribute("customer Account")] public str ParmCustomer(str _customer = customer) { customer = _customer; return customer; } [DataMemberAttribute('customerList'),SysOperationLabelAttribute("customer"),AifCollectionTypeAttribute("customerList", Types::String)] public List ParmcustomerList(List _customerList = customerList) { customerList = _customerList; return customerList; } 2). controller class public static void main(Args _args) ...