FAIL: test_recursive_frozendict_and_inst (test.test_pickle.InMemoryPickleTests.test_recursive_frozendict_and_inst) (proto=5)
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Traceback (most recent call last):
  File "/home/vstinner/python/main/Lib/test/pickletester.py", line 2852, in _test_recursive_collection_and_inst
    self.assertIs(list(x)[0].attr, x)
    ~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^
AssertionError: frozendict({<test.picklecommon.Object object at 0x200009adea0>: None}) is not frozendict({<test.picklecommon.Object object at 0x200009adea0>: None})