g_return_val_if_fail (GTK_IS_ASSISTANT (assistant), 0);
g_return_val_if_fail (GTK_IS_WIDGET (page), 0);
g_return_val_if_fail (page->parent == NULL, 0);
- g_return_val_if_fail (!GTK_WIDGET_TOPLEVEL (page), 0);
+ g_return_val_if_fail (!gtk_widget_is_toplevel (page), 0);
priv = assistant->priv;