get submenu tkinter object

Having nested (with sub menus added by .add_cascade) tkinter Menu object, is it possible to get the sub menu object?

I tried (menu_lab.py):

def main(root):
    top = tk.Menu(root)
    root.config(menu=top)
    top.add_command(label='Get sub', command=lambda t=top: get_sub(t))
    sub = tk.Menu(top)
    sub.add_command(label='Glider', command=lambda: print('Glider'))
    top.add_cascade(label='Insert', menu=sub)
    get_sub(top)


def get_sub(top):
    for i in range(top.index(tk.END) + 1):
        try:
            if top.entrycget(i, 'label') == 'Insert':
                sub = top.entrycget(i, 'menu')
                print(f'{sub = }')
        except tk.TclError:  # unknown option "-label"
            continue


if __name__ == '__main__':
    root = tk.Tk()
    main(root)
    root.mainloop()

it prints:

$ python menu_lab.py
sub = '.!menu.!menu'

Using Python 3.9.2, Debian 11

The cget method returns the internal name of the widget. You can use the universal widget method nametowidget to convert that name to the actual widget object:

sub = top.entrycget(i, 'menu')
menu = top.nametowidget(sub)