private async void save()
        {
            Requesting = true;
            var value = await Service.initiatePaiement(lastName, firstName, SecretCode, cardNumber, Devise, Panier.getTotal());

            if (value == ActionEvent.Pay_Success)
            {
                Panier.Books.Clear();
                FirstName  = string.Empty;
                LastName   = string.Empty;
                CardNumber = string.Empty;
                SecretCode = string.Empty;
                Messenger.Default.Send(ActionEvent.BagChanged);
            }

            Requesting = false;
            Messenger.Default.Send(value);
        }