recent change when passing a Union to a function

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2020-01-02.10:44:44.056>
labels = ['ctypes', 'type-bug', '3.8']
title = 'recent change when passing a Union to a function'
updated_at = <Date 2020-01-02.10:44:44.056>
user = 'https://bugs.python.org/KevinSchlossser'

bugs.python.org fields:

activity = <Date 2020-01-02.10:44:44.056>
actor = 'Kevin Schlossser'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['ctypes']
creation = <Date 2020-01-02.10:44:44.056>
creator = 'Kevin Schlossser'
dependencies = []
files = []
hgrepos = []
issue_num = 39188
keywords = []
message_count = 1.0
messages = ['359187']
nosy_count = 1.0
nosy_names = ['Kevin Schlossser']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue39188'
versions = ['Python 3.8']