+class MyRemoveObserver(ModelObserver):
+ async def on_change(self, delta, old, new, model):
+ if delta.type == 'remove':
+ assert(new.latest() == new)
+ assert(new.next() is None)
+ assert(new.dead)
+ assert(new.current)
+ assert(new.connected)
+ assert(new.previous().dead)
+ assert(not new.previous().current)
+ assert(not new.previous().connected)
+
+