PyByteArray_FromObject() has undocumented (and untested) behavior

GitHub fields:

assignee = 'https://github.com/serhiy-storchaka'
closed_at = None
created_at = <Date 2018-09-15.16:24:14.130>
labels = ['type-bug', '3.8']
title = 'PyByteArray_FromObject() has undocumented (and untested) behavior'
updated_at = <Date 2018-10-12.06:15:19.485>
user = 'https://github.com/ZackerySpytz'

bugs.python.org fields:

activity = <Date 2018-10-12.06:15:19.485>
actor = 'serhiy.storchaka'
assignee = 'serhiy.storchaka'
closed = False
closed_date = None
closer = None
components = []
creation = <Date 2018-09-15.16:24:14.130>
creator = 'ZackerySpytz'
dependencies = []
files = []
hgrepos = []
issue_num = 34696
keywords = ['patch']
message_count = 2.0
messages = ['325444', '327562']
nosy_count = 2.0
nosy_names = ['serhiy.storchaka', 'ZackerySpytz']
pr_nums = ['9332']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue34696'
versions = ['Python 3.8']