code: func (v *TreeModel) GetIterFirst() (*TreeIter, bool) {
  	var iter C.GtkTreeIter
  	c := C.gtk_tree_model_get_iter_first(v.native(), &iter)
  	if !gobool(c) {
  		return nil, false
  	}
  	t := &TreeIter{iter}
  	return t, true
  }
docs: // GetIterFirst() is a wrapper around gtk_tree_model_get_iter_first().