How ist the field named in which the series is saved?

I want of the supplier series (in this example the last 6-digit (L-0019). How can i get it. If I fetch from naming_series it does not work.

frappe.ui.form.on(‘Supplier’, {
refresh(frm) {
// Extrahieren der letzten 6 Zeichen des naming_series Wertes
var last_six = frm.doc.naming_series.slice(-6);
// Setzen des extrahierten Wertes in das Feld custom_supplier_number
frm.set_value(‘custom_supplier_number’, last_six);

Sorry I answered just myself. I am no programmer at all. But I should know that it ist the It works now