public static List <InvoiceItemViewModel> ConvertToInvoiceItemViewModelList(this IEnumerable <InvoiceItem> InvoiceItems)
        {
            List <InvoiceItemViewModel> InvoiceItemViewModels = new List <InvoiceItemViewModel>();

            foreach (InvoiceItem InvoiceItem in InvoiceItems)
            {
                InvoiceItemViewModels.Add(InvoiceItem.ConvertToInvoiceItemViewModel());
            }
            return(InvoiceItemViewModels);
        }