wrong annotation for typing.Match.groups()

[arnimarj]

Hi,

Just noticed that the annotation for typing.Match.groups() seems to be wrong. It's currently at ... -> Sequence[AnyStr]: ..., but I believe it should be ... -> Sequence[Optional[AnyStr]]: .... This documentation seems to agree: https://docs.python.org/3/library/re.html#re.Match.groups

import re

def matchalot(s: str) -> None:
	print('string', s)

	pattern = re.compile('^([1-9]a)([1-9]b)?([1-9]c)?$')
	search = pattern.search(s)
	assert(search)

	print('groups', search.groups())
	print('------------')


matchalot('3a')
matchalot('3a2b')
matchalot('3a1c')
matchalot('3a2b1c')

outputs this on Python 3.8:

string 3a
groups ('3a', None, None)
------------
string 3a2b
groups ('3a', '2b', None)
------------
string 3a1c
groups ('3a', None, '1c')
------------
string 3a2b1c
groups ('3a', '2b', '1c')
------------

Fix candidate here: #4381

[srittau]

Closing as duplicate of #3902. Please see there for some prior discussion. Unfortunately, it's not that easy to solve.