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FAIL: test_imap4_host_default_value (test.test_imaplib.TestImaplib)
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Traceback (most recent call last):
  File "/home/python/Lib/test/test_imaplib.py", line 94, in test_imap4_host_default_value
    self.assertIn(cm.exception.errno, expected_errnos)
AssertionError: 101 not found in [111, 99]

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I guess `errno.ENETUNREACH` should be added to the `expected_errnos` as it done within `test_create_connection` (test.test_socket.NetworkConnectionNoServer).