code: func (v *TreeModel) GetPath(iter *TreeIter) (*TreePath, error) {
  	c := C.gtk_tree_model_get_path(v.native(), iter.native())
  	if c == nil {
  		return nil, nilPtrErr
  	}
  	p := &TreePath{c}
  	runtime.SetFinalizer(p, (*TreePath).free)
  	return p, nil
  }
docs: // GetPath() is a wrapper around gtk_tree_model_get_path().