sorted.path to a path on the child model of tree.model.sort.
That is, sorted.path points to a location in tree.model.sort. The
returned path will point to the same location in the model not being
sorted. If sorted.path does not point to a location in the child model,
NULL is returned.gtkTreeModelSortConvertPathToChildPath(object, sorted.path)objectsorted.pathGtkTreePath to convertGtkTreePath] A newly allocated GtkTreePath, or NULL