The decode_header function does not always work correctly.

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2018-08-03.14:40:05.783>
labels = ['expert-email']
title = 'The decode_header function does not always work correctly.'
updated_at = <Date 2018-08-05.05:03:04.276>
user = 'https://bugs.python.org/2'

bugs.python.org fields:

activity = <Date 2018-08-05.05:03:04.276>
actor = 'xtreak'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['email']
creation = <Date 2018-08-03.14:40:05.783>
creator = '\xd0\x92\xd0\xbb\xd0\xb0\xd0\xb4 \xd0\x9a2'
dependencies = []
files = []
hgrepos = []
issue_num = 34330
keywords = []
message_count = 1.0
messages = ['323056']
nosy_count = 4.0
nosy_names = ['barry', 'r.david.murray', 'xtreak', '\xd0\x92\xd0\xbb\xd0\xb0\xd0\xb4 \xd0\x9a2']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = None
url = 'https://bugs.python.org/issue34330'
versions = ['Python 2.7']