error in tox: AttributeError: Can't pickle local object 'time_limit.<locals>.capture_results'

[gdemengin]

on macos with python 3.8 "tox -e py38" fails with this error

==============================
Failed 1 tests - output below:
==============================

tests.test_jenkins_sockets.JenkinsRequestTimeoutTests.test_jenkins_open_no_timeout
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Captured traceback:
~~~~~~~~~~~~~~~~~~~
    Traceback (most recent call last):

      File "/Users/gdm/workspace/python-jenkins/master/tests/test_jenkins_sockets.py", line 42, in test_jenkins_open_no_timeout
    time_limit(0.5, self.messages,

      File "/Users/gdm/workspace/python-jenkins/master/tests/helper.py", line 50, in time_limit
    p.start()

      File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/multiprocessing/process.py", line 121, in start
    self._popen = self._Popen(self)

      File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/multiprocessing/context.py", line 224, in _Popen
    return _default_context.get_context().Process._Popen(process_obj)

      File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/multiprocessing/context.py", line 284, in _Popen
    return Popen(process_obj)

      File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/multiprocessing/popen_spawn_posix.py", line 32, in __init__
    super().__init__(process_obj)

      File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/multiprocessing/popen_fork.py", line 19, in __init__
    self._launch(process_obj)

      File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/multiprocessing/popen_spawn_posix.py", line 47, in _launch
    reduction.dump(process_obj, fp)

      File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/multiprocessing/reduction.py", line 60, in dump
    ForkingPickler(file, protocol).dump(obj)

    AttributeError: Can't pickle local object 'time_limit.<locals>.capture_results'

according to https://stackoverflow.com/questions/72766345/attributeerror-cant-pickle-local-object-in-multiprocessing replacing multiprocessing by multiprocess could help

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/jjb/python-jenkins/+/865915