bpo-37062: Enum: add extended AutoNumber example (GH-22349) (GH-22369)

(cherry picked from commit 62e40d8450)

Co-authored-by: Ethan Furman <ethan@stoneleaf.us>
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Miss Islington (bot) 2020-09-22 20:57:48 -07:00 committed by GitHub
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@ -888,6 +888,32 @@ Using an auto-numbering :meth:`__new__` would look like::
>>> Color.GREEN.value
2
To make a more general purpose ``AutoNumber``, add ``*args`` to the signature::
>>> class AutoNumber(NoValue):
... def __new__(cls, *args): # this is the only change from above
... value = len(cls.__members__) + 1
... obj = object.__new__(cls)
... obj._value_ = value
... return obj
...
Then when you inherit from ``AutoNumber`` you can write your own ``__init__``
to handle any extra arguments::
>>> class Swatch(AutoNumber):
... def __init__(self, pantone='unknown'):
... self.pantone = pantone
... AUBURN = '3497'
... SEA_GREEN = '1246'
... BLEACHED_CORAL = () # New color, no Pantone code yet!
...
>>> Swatch.SEA_GREEN
<Swatch.SEA_GREEN: 2>
>>> Swatch.SEA_GREEN.pantone
'1246'
>>> Swatch.BLEACHED_CORAL.pantone
'unknown'
.. note::

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@ -1678,6 +1678,7 @@ Févry Thibault
Lowe Thiderman
Nicolas M. Thiéry
James Thomas
Reuben Thomas
Robin Thomas
Brian Thorne
Christopher Thorne