private CartClear GetCartClear(Cart cart)
 {
     CartClear cartClear = new CartClear();
     cartClear.AssociateTag = AssociateTag;
     cartClear.AWSAccessKeyId = AWSAccessKeyId;
     CartClearRequest clearReq = new CartClearRequest();
     clearReq.CartId = cart.CartId;
     clearReq.HMAC = cart.HMAC;
     cartClear.Request = new CartClearRequest[] {clearReq};
     return cartClear;
 }
 private void WriteCartInfo(Cart cart)
 {
     using (StreamWriter writer = new StreamWriter(CartInfoPath)) {
         writer.WriteLine(cart.CartId + "," + cart.HMAC);
     }
 }