Menu.insertSubmenu

void insertSubmenu(int position, string label, gio.menu_model.MenuModel submenu)

Convenience function for inserting a submenu menu item into menu. Combine [gio.menu_item.MenuItem.newSubmenu] and [gio.menu.Menu.insertItem] for a more flexible alternative.

Parameters

`position`	the position at which to insert the item
`label`	the section label, or null
`submenu`	a #GMenuModel with the items of the submenu