Robert Latest <boblatest at yahoo.com> writes: > > flist.sort(key=lambda f: f.mod_date.toordinal) > > It doesn't throw an error any more, but neither does it sort the list. This, > however, works: Oh, I didn't realize that toordinal was a callable, given your earlier sample. You want: flist.sort(key=lambda f: f.mod_date.toordinal() )