======================================================================
FAIL: /Doc/howto/enum.rst
Doctest: enum.rst
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Lib/doctest.py", line 2239, in runTest
    raise self.failureException(self.format_failure(new.getvalue()))
AssertionError: Failed doctest test for enum.rst
  File "/Doc/howto/enum.rst", line 0
----------------------------------------------------------------------
File "/Doc/howto/enum.rst", line 1395, in enum.rst
Failed example:
    class Color(DuplicateFreeEnum):
        RED = 1
        GREEN = 2
        BLUE = 3
        GRENE = 2
Expected:
    Traceback (most recent call last):
      ...
    ValueError: aliases not allowed in DuplicateFreeEnum:  'GRENE' --> 'GREEN'
    Error calling __set_name__ on '_proto_member' instance 'GRENE' in 'Color'
Got:
    Traceback (most recent call last):
      File "/Lib/doctest.py", line 1351, in __run
        exec(compile(example.source, filename, "single",
      File "<doctest enum.rst[160]>", line 1, in <module>
        class Color(DuplicateFreeEnum):
      File "/Lib/enum.py", line 566, in __new__
        raise exc
      File "/Lib/enum.py", line 275, in __set_name__
        enum_member.__init__(*args)
      File "<doctest enum.rst[159]>", line 7, in __init__
        raise ValueError(
    ValueError: aliases not allowed in DuplicateFreeEnum:  'GRENE' --> 'GREEN'
----------------------------------------------------------------------