V15: Using Web Form but after load is not working!

Hi all,
On V14 and V15 the before code that was working on V13
frappe.web_form.events.on(‘after_load’, myfunction) is not working.
I have seen on Frappe docs that should now be
frappe.web_form.after_load = () => {
** frappe.msgprint(‘Please fill all values carefully’);**
}

But after all tests still not working… that code being inside of frappe.ready(function() or outside does not work.

Anyone with a solution ?