Or how about: if ISortableSequence.isImplementedBy(seq): seq.sort() Who's to say the sort attribute is callable with no args? wocka, wocka ;^) -Casey On Tuesday 03 December 2002 03:50 am, Guido van Rossum wrote: > > if isinstance(seq, list): > > seq.sort() >=20 > Make that >=20 > if hasattr(seq, 'sort'): > seq.sort() >=20 > --Guido van Rossum (home page: http://www.python.org/~guido/)