@staticmethod seems to work with setUpClass, but docs say it shouldn't

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2019-04-09.05:40:35.008>
labels = ['3.7', 'type-bug', 'library']
title = "@staticmethod seems to work with setUpClass, but docs say it shouldn't"
updated_at = <Date 2019-04-09.21:34:14.473>
user = 'https://bugs.python.org/PeterdeBlanc'

bugs.python.org fields:

activity = <Date 2019-04-09.21:34:14.473>
actor = 'brett.cannon'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2019-04-09.05:40:35.008>
creator = 'Peter de Blanc'
dependencies = []
files = ['48251']
hgrepos = []
issue_num = 36569
keywords = []
message_count = 3.0
messages = ['339700', '339705', '339810']
nosy_count = 6.0
nosy_names = ['brett.cannon', 'rbcollins', 'ezio.melotti', 'michael.foord', 'xtreak', 'Peter de Blanc']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue36569'
versions = ['Python 3.6', 'Python 3.7']