Misleading documentation for NotImplemented

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2019-12-20.16:42:56.150>
labels = ['3.8', 'type-feature', '3.7', '3.9', 'docs']
title = 'Misleading documentation for NotImplemented'
updated_at = <Date 2019-12-28.07:11:38.640>
user = 'https://github.com/Murali'

bugs.python.org fields:

activity = <Date 2019-12-28.07:11:38.640>
actor = 'terry.reedy'
assignee = 'docs@python'
closed = False
closed_date = None
closer = None
components = ['Documentation']
creation = <Date 2019-12-20.16:42:56.150>
creator = 'murali'
dependencies = []
files = []
hgrepos = []
issue_num = 39111
keywords = []
message_count = 5.0
messages = ['358719', '358722', '358723', '358726', '358752']
nosy_count = 3.0
nosy_names = ['steven.daprano', 'docs@python', 'murali']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue39111'
versions = ['Python 3.7', 'Python 3.8', 'Python 3.9']