# Copyright (c) 2007, Enthought, Inc. # License: BSD Style. #--[Imports]-------------------------------------------------------------------- from traits.api import HasTraits, Trait, Instance #--[Code]----------------------------------------------------------------------- # Shows the incorrect way of defining mutually-referring classes. try: class Chicken ( HasTraits ): # Won't work: 'Egg' not defined yet: hatched_from = Instance( Egg ) class Egg ( HasTraits ): # If we move this class to the top, then this line won't work, because # 'Chicken' won't be defined yet: created_by = Instance( Chicken ) except NameError, excp: print excp