def __setattr__(self, attr, value):
if attr in [
"position", "label", "shape", "size", "color", "filled",
"comment"
]:
old_value = getattr(self, attr, None)
object.__setattr__(self, attr, value)
self.notify_observers(attr, old_value=old_value)
else:
Observable.__setattr__(self, attr, value)
