public IActionResult DownloadInvoice(int invoiceNumber)
        {
            //ToDo :: Need more security to check if the authorized user is the owner of this invoice. (for now it is pretty fine)
            var pdfFile = _pdf.GetInvoicePdfFile(invoiceNumber);

            if (pdfFile != null)
            {
                return(pdfFile);
            }
            return(RedirectToAction("Error", "Home"));
        }