code: func IconViewNewWithModel(model ITreeModel) (*IconView, error) {
  	c := C.gtk_icon_view_new_with_model(model.toTreeModel())
  	if c == nil {
  		return nil, nilPtrErr
  	}
  	obj := glib.Take(unsafe.Pointer(c))
  	return wrapIconView(obj), nil
  }
docs: // IconViewNewWithModel is a wrapper around gtk_icon_view_new_with_model().