ExtensionFileLoader Does Not Implement invalidate_caches

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2021-04-12.20:54:59.834>
labels = ['type-bug', '3.9']
title = 'ExtensionFileLoader Does Not Implement invalidate_caches'
updated_at = <Date 2021-04-12.20:54:59.834>
user = 'https://github.com/insertinterestingnamehere'

bugs.python.org fields:

activity = <Date 2021-04-12.20:54:59.834>
actor = 'Ian.H'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = []
creation = <Date 2021-04-12.20:54:59.834>
creator = 'Ian.H'
dependencies = []
files = []
hgrepos = []
issue_num = 43819
keywords = []
message_count = 1.0
messages = ['390905']
nosy_count = 1.0
nosy_names = ['Ian.H']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue43819'
versions = ['Python 3.9']