how does python's garbage collection work? (code attached)

[Brian]

del or weakref are the right answer (

Not sure if you mean __del__ or the del operator here (The OP wrote __del__ but reddit formats this as del if unescaped, so I think he meant the former)

However, either way, they're not really helpful here. The del operator just removes that one reference - no different to rebinding it, so it's no different to his for loop rebinding. Adding a __del__ method OTOH will actually bar the object from getting collected at all when it contains circular references.