How to bind event on sap.m.MessageBox in sapui5?

I am using this MessageBox demo in Explored. How to bind event on buttons: MessageBox.Action.YES/"Custom Button" ?

In MessageBox.show api, I only found onClose parameters.

Here's an example that shows how to handle the OK, CANCEL, and a "Custom Button" within the MessageBox.confirm method:

    MessageBox.confirm(sText, {
        title: sTitle,
        initialFocus: sap.m.MessageBox.Action.CANCEL,
        onClose: function(sButton) {
            if (sButton === MessageBox.Action.OK) {
                // Action for the OK button
            } else if (sButton === MessageBox.Action.CANCEL) {
                // Action for the CANCEL button
            } else if (sButton === "Custom Button") { // Fixed the missing quote here
                // Action for the custom button
            }
        }
    });