in version 1.37 of formmethod.py has been added a constructor to the String class, to add a min/max lenght check for the string. That's a cool idea, but the implementation destroyed the behaviour of all derived classes :). def __init__(self, name, default=None, shortDesc=None, longDesc=None, hints=None, allowNone=1, min=0, max=None): Argument.__init__(self, name, default=None, shortDesc=None, longDesc=None, hints=None, allowNone=1) self.min = min self.max = max you can see that in calling the Argument.__init__ constructor, all values are reset to None. issued to the bugtracker, with simple patch. http://www.twistedmatrix.com/users/roundup.twistd/twisted/issue296 -- Linux webmaster & sysadmin pradu@pradu.it