get_pages
Description:
Returns a [iface@Gio.
ListModel] that contains the pages of the stack.
This can be used to keep an up-to-date view. The model also implements [iface@Gtk.SelectionModel] and can be used to track and change the visible page.
Parameters:
| this | a view stack | 
Returns:
| a `GtkSelectionModel` for the stack's children |