dictobject dictviews don't return NotImplemented for unrecognized types.

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2019-10-20.15:32:28.093>
labels = ['3.8', 'type-bug', '3.7', '3.9']
title = "dictobject dictviews don't return NotImplemented for unrecognized types."
updated_at = <Date 2019-11-22.20:58:55.538>
user = 'https://github.com/JulienPalard'

bugs.python.org fields:

activity = <Date 2019-11-22.20:58:55.538>
actor = 'mdk'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = []
creation = <Date 2019-10-20.15:32:28.093>
creator = 'mdk'
dependencies = []
files = []
hgrepos = []
issue_num = 38538
keywords = []
message_count = 5.0
messages = ['355007', '355032', '355155', '355517', '357322']
nosy_count = 2.0
nosy_names = ['methane', 'mdk']
pr_nums = []
priority = 'normal'
resolution = None
stage = 'test needed'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue38538'
versions = ['Python 3.7', 'Python 3.8', 'Python 3.9']