Intercept HTML5 Web Notifications in a browser environment

I would like to intercept HTML5 Web Notifications. I have read the following answer where a user suggests that it is possible to override the window.Notification object with your own object that will act as a proxy. I tried to do that but couldn't manage it to work. Below is the JavaScript code I am injecting when a page has been loaded:

function setNotificationCallback(callback) {

    const OldNotify = window.Notification;
    OldNotify.requestPermission();

    const newNotify = (title, opt) => {
        callback(title, opt);
        return new OldNotify(title, opt);
    };
    newNotify.requestPermission = OldNotify.requestPermission.bind(OldNotify);
    Object.defineProperty(newNotify, 'permission', {
        get: () => {
            return OldNotify.permission;
        }
    });

    window.Notification = newNotify;
}
function notifyCallback(title, opt) {
    console.log("title", title); // this never gets called
}

window.Notification.requestPermission(function (permission) {
    if (permission === "granted") {
        setNotificationCallback(notifyCallback);
    }
})

from Intercept HTML5 Web Notifications in a browser environment