code: func (v *Assistant) GetNthPage(pageNum int) (*Widget, error) {
  	c := C.gtk_assistant_get_nth_page(v.native(), C.gint(pageNum))
  	if c == nil {
  		return nil, fmt.Errorf("page %d is out of bounds", pageNum)
  	}
  
  	obj := glib.Take(unsafe.Pointer(c))
  	return wrapWidget(obj), nil
  }
docs: // GetNthPage is a wrapper around gtk_assistant_get_nth_page().