public string GetDocumentByType()
        {
            try
            {
                string transactionId = "df07e2dd-4260-4d5d-93fa-2042db218bdd"; // ???? get from DB ??

                DTPClient dtpClient = new DTPClient(transactionId);
                Document doc = dtpClient.GetDocumentByType(DTPClient.DocumentTypes.CONTRACT);
                dtpClient.SaveDocumentToFile(doc,  @"E:\Contrats\" + dtpClient.TransactionId);

                return "OK";
            }
            catch
            {
                //LOG
                return "KO";
            }
        }
        public string GetDocumentsByType()
        {
            try
            {
                string transactionId = "df07e2dd-4260-4d5d-93fa-2042db218bdd"; // ???? get from DB ??

                DTPClient dtpClient = new DTPClient(transactionId);
                byte[] zip = dtpClient.GetDocumentsByType(new List<string>() { DTPClient.DocumentTypes.CONTRACT.ToString() }.ToArray());
                dtpClient.SaveDocumentToFile(zip, @"E:\Contrats\" + dtpClient.TransactionId, "Contrat.zip");

                return "OK";
            }
            catch
            {
                //LOG
                return "KO";
            }
        }