$ ./python.exe -Om unittest test.test_imaplib
...
======================================================================
ERROR: test_dump_ur (test.test_imaplib.ThreadedNetworkedTests.test_dump_ur)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/.../dev/cpython/Lib/test/support/threading_helper.py", line 63, in decorator
    return func(*args)
           ^^^^^^^^^^^
  File "/Users/.../dev/cpython/Lib/test/test_imaplib.py", line 948, in test_dump_ur
    with mock.patch.object(imap, '_mesg') as mock_mesg:
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/.../dev/cpython/Lib/unittest/mock.py", line 1427, in __enter__
    original, local = self.get_original()
                      ^^^^^^^^^^^^^^^^^^^
  File "/Users/.../dev/cpython/Lib/unittest/mock.py", line 1400, in get_original
    raise AttributeError(
    ^^^^^^^^^^^^^^^^^^^^^
AttributeError: <imaplib.IMAP4 object at 0x1032a3bc0> does not have the attribute '_mesg'

----------------------------------------------------------------------
Ran 103 tests in 6.203s

FAILED (errors=1, skipped=55)

./python.exe -Om unittest test.test_zipimport
...
----------------------------------------------------------------------
Ran 103 tests in 6.156s

OK (skipped=56)