% python2.4 ~/tmp/picklecycle.py
(<class __main__.A at 0x81dae9c>, '0x81e790c')
memoized 0x81e790c
(<type 'dict'>, '0x81e846c') <{'b': <__main__.B instance at 0x81e78ec>, 'name': 'moe'}>
memoized 0x81e846c
(<type 'str'>, '0x8181440') <b>
memoized 0x8181440
(<class __main__.B at 0x81daf8c>, '0x81e78ec')
memoized 0x81e78ec
(<type 'dict'>, '0x81e83e4') <{'a': <__main__.A instance at 0x81e790c>, 'name': 'manny'}>
memoized 0x81e83e4
(<type 'str'>, '0x8181360') <a>
memoized 0x8181360
(<type 'str'>, '0x816a880') <name>
memoized 0x816a880
(<type 'str'>, '0x81c5420') <manny>
memoized 0x81c5420
(<type 'str'>, '0x81c5400') <moe>
memoized 0x81c5400
% python2.4 ~/tmp/picklecycle.py
(<type 'type'>, '0x822fefc') <<class '__main__.A'>>
memoized 0x822fefc
(<type 'str'>, '0x81c5400') <moe>
memoized 0x81c5400
(<type 'type'>, '0x823256c') <<class '__main__.B'>>
memoized 0x823256c
(<type 'str'>, '0x81c5420') <manny>
memoized 0x81c5420
(<type 'tuple'>, '0x81e7aac') <('manny',)>
memoized 0x81e7aac
(<class '__main__.B'>, '0x81e796c')
memoized 0x81e796c
(<type 'dict'>, '0x81e82d4') <{'a': <__main__.A object at 0x81e79ac>, 'name': 'manny'}>
memoized 0x81e82d4
(<type 'str'>, '0x8181360') <a>
memoized 0x8181360
(<type 'tuple'>, '0x81c494c') <('moe', <__main__.B object at 0x81e796c>)>
memoized 0x81c494c
(<class '__main__.A'>, '0x81e79ac')
memoized 0x81e79ac
(<type 'dict'>, '0x81e846c') <{'b': <__main__.B object at 0x81e796c>, 'name': 'moe'}>
memoized 0x81e846c
(<type 'str'>, '0x8181440') <b>
memoized 0x8181440
(<type 'str'>, '0x816a880') <name>
memoized 0x816a880
(<type 'tuple'>, '0x81c47ec') <('moe', <__main__.B object at 0x81e796c>)>
memoized 0x81c47ec
(<class '__main__.A'>, '0x81e79ac')
Traceback (most recent call last):
  File "/home/titan/skipm/tmp/picklecycle.py", line 32, in ?
    pickler.dump(a)
  File "/home/titan/skipm/local/lib/python2.4/pickle.py", line 231, in dump
    self.save(obj)
  File "/home/titan/skipm/local/lib/python2.4/pickle.py", line 345, in save
    self.save_reduce(obj=obj, *rv)
  File "/home/titan/skipm/local/lib/python2.4/pickle.py", line 426, in save_reduce
    self.memoize(obj)
  File "/home/titan/skipm/local/lib/python2.4/pickle.py", line 257, in memoize
    assert id(obj) not in self.memo
AssertionError