func (store *AccountStore) cancel_transaction(w http.ResponseWriter, r *http.Request) {
	if trans := store.get_transaction(w, r); trans != nil {
		if err := trans.Cancel(); err != nil {
			services.Http_application_error(w, r, err)
		}
		services.Http_respond(w, r, nil, http.StatusOK)
	}
}
func (payments *Payments) cancel_payment(w http.ResponseWriter, r *http.Request) {
	if payment := payments.get_payment(w, r, true); payment != nil {
		if err := payment.Cancel(); err != nil {
			services.Http_application_error(w, r, err)
		} else {
			services.Http_respond(w, r, nil, http.StatusOK)
		}
	}
}
func (catalog *Catalog) cancel_shipment(w http.ResponseWriter, r *http.Request) {
	if shipment := catalog.get_shipment(w, r); shipment != nil {
		if err := shipment.Cancel(); err != nil {
			services.Http_application_error(w, r, err)
		} else {
			services.Http_respond(w, r, nil, http.StatusOK)
		}
	}
}