Problem with contextlib.nullcontext

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2018-07-07.17:33:25.936>
labels = ['3.8', '3.9', '3.10', 'performance']
title = 'Problem with contextlib.nullcontext'
updated_at = <Date 2020-11-02.14:13:49.172>
user = 'https://github.com/serhiy-storchaka'

bugs.python.org fields:

activity = <Date 2020-11-02.14:13:49.172>
actor = 'iritkatriel'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = []
creation = <Date 2018-07-07.17:33:25.936>
creator = 'serhiy.storchaka'
dependencies = []
files = []
hgrepos = []
issue_num = 34067
keywords = ['patch']
message_count = 8.0
messages = ['321226', '321254', '321319', '321322', '321461', '321463', '321472', '378332']
nosy_count = 5.0
nosy_names = ['ncoghlan', 'eric.smith', 'serhiy.storchaka', 'miss-islington', 'iritkatriel']
pr_nums = ['8158', '8199']
priority = 'normal'
resolution = None
stage = 'needs patch'
status = 'open'
superseder = None
type = 'resource usage'
url = 'https://bugs.python.org/issue34067'
versions = ['Python 3.8', 'Python 3.9', 'Python 3.10']