public HttpResponseMessage Delete(string bookReferenceNumber) { Repository repository = new Repository(); // se não encontrar nenhuma reserva com o numero informado, retorna 400 IBook book = repository.FindReservation(bookReferenceNumber); if (book == null) return new HttpResponseMessage(HttpStatusCode.BadRequest); // cancelando e apagando do disco repository.CancelReservation(bookReferenceNumber); return new HttpResponseMessage(HttpStatusCode.OK); }