Hmm, going 'the other way', you are allowed an extra , but you can't have (,) as the empty tuple.:
>>> (1,2,) (1, 2) >>> (1,) (1,) >>> (,) ... Traceback ( File "<interactive input>", line 1 (,) ^ SyntaxError: invalid syntax -- Pad. -- http://mail.python.org/mailman/listinfo/python-list