AutoNumber class in enum documentation: support *args in constructor

[rrt]

BPO	37062
Nosy	@ethanfurman, @ambv, @miss-islington
PRs	bpo-37062: Enum - add extended AutoNumber example #22349 [3.8] bpo-37062: Enum: add extended AutoNumber example (GH-22349) #22369 [3.9] bpo-37062: Enum: add extended AutoNumber example (GH-22349) #22370
Files	foo.py: Demo code

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = 'https://github.com/ethanfurman'
closed_at = <Date 2020-09-23.03:59:37.509>
created_at = <Date 2019-05-27.06:03:00.596>
labels = ['3.10', 'docs']
title = '`AutoNumber` class in enum documentation: support *args in constructor'
updated_at = <Date 2020-10-05.16:10:20.181>
user = 'https://bugs.python.org/rrt'

bugs.python.org fields:

activity = <Date 2020-10-05.16:10:20.181>
actor = 'lukasz.langa'
assignee = 'ethan.furman'
closed = True
closed_date = <Date 2020-09-23.03:59:37.509>
closer = 'ethan.furman'
components = ['Documentation']
creation = <Date 2019-05-27.06:03:00.596>
creator = 'rrt'
dependencies = []
files = ['48365']
hgrepos = []
issue_num = 37062
keywords = ['patch']
message_count = 8.0
messages = ['343607', '343608', '377291', '377292', '377355', '377356', '377357', '378056']
nosy_count = 5.0
nosy_names = ['docs@python', 'ethan.furman', 'lukasz.langa', 'rrt', 'miss-islington']
pr_nums = ['22349', '22369', '22370']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue37062'
versions = ['Python 3.10']

[rrt]

By changing one line of AutoNumber:

    def __new__(cls):

to

    def __new__(cls, *args):

Enums derived from AutoNumber can now support constructors that take named arguments; for example:

class Color(AutoNumber):
    def __init__(self, pantone=None):
        self.pantone = pantone or 'unknown'

class Swatch(Color):
    AUBURN = ('3497')
    SEA_GREEN = ('1246')
    BLEACHED_CORAL = () # New color, no Pantone code yet!

Without the change, one gets the error:

TypeError: __new__() takes 1 positional argument but 2 were given

I attach runnable demonstration code.

[rrt]

Just to be clear, the proposed change to the documentation is simply to add ", *args" to the argument list of AutoNumber.__new__.

[ethanfurman]

The only AutoNumber in the stdlib is as an example in the docs. Were you thinking of something else?

[rrt]

That's the one I was thinking of: the example in the docs.

[ethanfurman]

New changeset 5acc1b5 by Miss Islington (bot) in branch '3.8':
bpo-37062: Enum: add extended AutoNumber example (GH-22349) (GH-22369)
5acc1b5

[ethanfurman]

New changeset 64362c2 by Miss Islington (bot) in branch '3.9':
bpo-37062: Enum: add extended AutoNumber example (GH-22349) (GH-22370)
64362c2

[ethanfurman]

Thank you, Reuben!

[ambv]

New changeset e8165e7 by Łukasz Langa (Miss Islington (bot)) in branch '3.9':
bpo-37062: Enum: add extended AutoNumber example (GH-22349) (GH-22370)
e8165e7