$ ./python -We -m test -vuall test_argparse -m test_invalid_args
...
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ERROR: test_invalid_args (test.test_argparse.TestIntermixedArgs.test_invalid_args)
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Traceback (most recent call last):
  File "/home/serhiy/py/cpython/Lib/test/test_argparse.py", line 5815, in test_invalid_args
    parser.parse_intermixed_args(['hello', '--foo'])
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^
  File "/home/serhiy/py/cpython/Lib/argparse.py", line 2386, in parse_intermixed_args
    args, argv = self.parse_known_intermixed_args(args, namespace)
                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
  File "/home/serhiy/py/cpython/Lib/argparse.py", line 2440, in parse_known_intermixed_args
    warn('Do not expect %s in %s' % (action.dest, namespace))
    ~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
UserWarning: Do not expect foo in Namespace(foo=[])

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