from Source import Source class Event(Source, object): def __init__(self): Source.__init__(self) self.evt = None def getCurrentEvent(self): return self.evt event = property(getCurrentEvent) def newEvent(self, event): if not self.evt or self.evt != event: self.evt = event if not event: self.changed((self.CHANGED_CLEAR,)) else: self.changed((self.CHANGED_ALL,))