Failure on x86-64 High Sierra 3.8:
https://buildbot.python.org/all/#/builders/226/builds/519

Please fix tests, or revert your change:
https://pythondev.readthedocs.io/ci.html#revert-on-fail

======================================================================
ERROR: test_lockf_exclusive (test.test_fcntl.TestFcntl)
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Traceback (most recent call last):
  File "/Users/buildbot/buildarea/3.8.billenstein-sierra/build/Lib/test/test_fcntl.py", line 149, in test_lockf_exclusive
    p.start()
  File "/Users/buildbot/buildarea/3.8.billenstein-sierra/build/Lib/multiprocessing/process.py", line 121, in start
    self._popen = self._Popen(self)
  File "/Users/buildbot/buildarea/3.8.billenstein-sierra/build/Lib/multiprocessing/context.py", line 224, in _Popen
    return _default_context.get_context().Process._Popen(process_obj)
  File "/Users/buildbot/buildarea/3.8.billenstein-sierra/build/Lib/multiprocessing/context.py", line 283, in _Popen
    return Popen(process_obj)
  File "/Users/buildbot/buildarea/3.8.billenstein-sierra/build/Lib/multiprocessing/popen_spawn_posix.py", line 32, in __init__
    super().__init__(process_obj)
  File "/Users/buildbot/buildarea/3.8.billenstein-sierra/build/Lib/multiprocessing/popen_fork.py", line 19, in __init__
    self._launch(process_obj)
  File "/Users/buildbot/buildarea/3.8.billenstein-sierra/build/Lib/multiprocessing/popen_spawn_posix.py", line 47, in _launch
    reduction.dump(process_obj, fp)
  File "/Users/buildbot/buildarea/3.8.billenstein-sierra/build/Lib/multiprocessing/reduction.py", line 60, in dump
    ForkingPickler(file, protocol).dump(obj)
AttributeError: Can't pickle local object 'TestFcntl.test_lockf_exclusive.<locals>.try_lockf_on_other_process'

======================================================================
ERROR: test_lockf_share (test.test_fcntl.TestFcntl)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/buildbot/buildarea/3.8.billenstein-sierra/build/Lib/test/test_fcntl.py", line 163, in test_lockf_share
    p.start()
  File "/Users/buildbot/buildarea/3.8.billenstein-sierra/build/Lib/multiprocessing/process.py", line 121, in start
    self._popen = self._Popen(self)
  File "/Users/buildbot/buildarea/3.8.billenstein-sierra/build/Lib/multiprocessing/context.py", line 224, in _Popen
    return _default_context.get_context().Process._Popen(process_obj)
  File "/Users/buildbot/buildarea/3.8.billenstein-sierra/build/Lib/multiprocessing/context.py", line 283, in _Popen
    return Popen(process_obj)
  File "/Users/buildbot/buildarea/3.8.billenstein-sierra/build/Lib/multiprocessing/popen_spawn_posix.py", line 32, in __init__
    super().__init__(process_obj)
  File "/Users/buildbot/buildarea/3.8.billenstein-sierra/build/Lib/multiprocessing/popen_fork.py", line 19, in __init__
    self._launch(process_obj)
  File "/Users/buildbot/buildarea/3.8.billenstein-sierra/build/Lib/multiprocessing/popen_spawn_posix.py", line 47, in _launch
    reduction.dump(process_obj, fp)
  File "/Users/buildbot/buildarea/3.8.billenstein-sierra/build/Lib/multiprocessing/reduction.py", line 60, in dump
    ForkingPickler(file, protocol).dump(obj)
AttributeError: Can't pickle local object 'TestFcntl.test_lockf_share.<locals>.try_lockf_on_other_process'