Tabelleneintrag beim Speichern ändern

frappe.ui.form.on('Quotation', {
	validate(frm) {
		console.log("Trigger validate");
        //frappe.model.set_value("Quotation Item", ctn, value);
        console.log(frm.doc.items);
        for (let i = 0; i < frm.doc.items.length; i++) {
            var item = frm.doc.items[i];
            if(item.positionsart != "Standard"){
                frappe.model.set_value(item.doctype, item.name,"rate","0");
                frm.refresh_fields("rate");   
            }
	    }
	}
});