paul j3 added the comment: In my suggestion I used if 'current_value is default': without going into detail. The use of an 'is' test for integer values is tricky, as discussed in http://bugs.python.org/issue18943 int("42") is 42 # True int("257") is 257 # False As with your 'self.reset_dest', in 18943 I suggested using a boolean flag instead of the 'is' test. ---------- _______________________________________ Python tracker <report@bugs.python.org> <http://bugs.python.org/issue16399> _______________________________________