_setDiscardableProperty(oParams) {
			const oWizard = this.byId("shoppingCartWizard");
			if (oWizard.getProgressStep() !== oParams.discardStep) {
				MessageBox.warning(oParams.message, {
					actions: [MessageBox.Action.YES,
						MessageBox.Action.NO],
					onClose: (oAction) => {
						if (oAction === MessageBox.Action.YES) {
							oWizard.discardProgress(oParams.discardStep);
							this._oHistory[oParams.historyPath] = this.getModel().getProperty(oParams.modelPath);
						} else {
							this.getModel().setProperty(oParams.modelPath, this._oHistory[oParams.historyPath]);
						}
					}
				});
			} else {
				this._oHistory[oParams.historyPath] = this.getModel().getProperty(oParams.modelPath);
			}
		}
Called from both <code>setPaymentMethod</code> and <code>setDifferentDeliveryAddress</code> functions.
Shows warning message if user changes previously selected choice.
@param {Object} oParams Object containing message text, model path and WizardSteps