csv.Sniffer().sniff(0) returns a value without the "strict" attribute

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2016-12-12.19:38:54.778>
labels = ['type-bug', 'library']
title = 'csv.Sniffer().sniff(0) returns a value without the "strict" attribute'
updated_at = <Date 2017-01-02.02:49:54.964>
user = 'https://bugs.python.org/4Dummies'

bugs.python.org fields:

activity = <Date 2017-01-02.02:49:54.964>
actor = 'ppperry'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2016-12-12.19:38:54.778>
creator = '4Dummies'
dependencies = []
files = []
hgrepos = []
issue_num = 28952
keywords = []
message_count = 1.0
messages = ['283041']
nosy_count = 1.0
nosy_names = ['4Dummies']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue28952'
versions = ['Python 3.5']