Copying functions doesn't actually copy them

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2020-03-01.03:42:42.779>
labels = ['type-bug', 'library', '3.9']
title = "Copying functions doesn't actually copy them"
updated_at = <Date 2022-03-28.22:19:55.266>
user = 'https://github.com/stevendaprano'

bugs.python.org fields:

activity = <Date 2022-03-28.22:19:55.266>
actor = 'vstinner'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2020-03-01.03:42:42.779>
creator = 'steven.daprano'
dependencies = []
files = []
hgrepos = []
issue_num = 39805
keywords = []
message_count = 7.0
messages = ['363039', '363041', '413163', '413178', '413180', '413182', '416223']
nosy_count = 4.0
nosy_names = ['vstinner', 'steven.daprano', 'serhiy.storchaka', 'Numerlor']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue39805'
versions = ['Python 3.9']