Type of callback used to calculate the next page in a `GtkAssistant`.
It’s called both for computing the next page when the user presses the “forward” button and for handling the behavior of the “last” button.
See [method@Gtk.Assistant.set_forward_page_func].
| current_page |
The page number used to calculate the next page. |
| data |
user data. |
|
The next page number |