code: func (v *TreeModelFilter) ConvertIterToChildIter(filterIter *TreeIter) *TreeIter {
  	var iter C.GtkTreeIter
  	C.gtk_tree_model_filter_convert_iter_to_child_iter(v.native(), &iter, filterIter.native())
  	t := &TreeIter{iter}
  	return t
  }
docs: // ConvertIterToChildIter is a wrapper around gtk_tree_model_filter_convert_child_iter_to_iter().