child.path to a path relative to tree.model.sort. That is,
child.path points to a path in the child model. The returned path will
point to the same row in the sorted model. If child.path isn't a valid
path on the child model, then NULL is returned.gtkTreeModelSortConvertChildPathToPath(object, child.path)objectchild.pathGtkTreePath to convertGtkTreePath] A newly allocated GtkTreePath, or NULL