private static List <SalesOrderItemModel> SerializeSalesOrderItems(IEnumerable <SalesOrderItem> orderItems)
 {
     return(orderItems.Select(item => new SalesOrderItemModel
     {
         Id = item.Id,
         Quantity = item.Quantity,
         Product = ProductMapper.SerializeProductModel(item.Product)
     }).ToList());
 }
        ///<summary>
        /// Maps an InvoiceModel (view model) to a SalesOrder (data) model
        ///</summary>
        ///<param name="invoice"></param>
        ///<returns></returns>

        public static SalesOrder SerializeInvoiceOrder(InvoiceModel invoice)
        {
            var salesOrderItems = invoice.LineItems.Select(item => new SalesOrderItem
            {
                Id       = item.Id,
                Quantity = item.Quantity,
                Product  = ProductMapper.SerializeProductModel(item.Product)
            }).ToList();

            return(new SalesOrder
            {
                SalesOrderItems = salesOrderItems,
                UpdatedOn = DateTime.UtcNow,
                CreatedOn = DateTime.UtcNow
            });
        }