Once again, > implementation detail There is no guarantee that even CPython will keep the current behaviour. Ultimately, the promise you're given is that __de

Once again, > implementation detail There is no guarantee that even CPython will keep the current behaviour. Ultimately, the promise you're given is that __del__ might be invoked by the system some point between "the object has no live references" and "never". The original assertion gives a much closer intuition than your description of the current behaviour.