Add Python 3.8 compatibility to type annotations.

.coveragerc

@@ -2,6 +2,7 @@
 omit =
 	# leading `*/` for pytest-dev/pytest-cov#456
 	*/.tox/*
+	*/compat/*
 disable_warnings =
 	couldnt-parse
 

jaraco/collections/__init__.py

@@ -5,12 +5,14 @@
 import copy
 import functools
 import random
-from collections.abc import Container, Iterable, Mapping, MutableMapping
+from collections.abc import Container, Iterable, Mapping
 from typing import Any, Callable, Union
 
 import jaraco.text
 from more_itertools import consume
 
+from .compat.py38 import MutableMapping
+
 
 _Matchable = Union[Callable, Container, Iterable, re.Pattern]
 

jaraco/collections/compat/py38.py

@@ -0,0 +1,8 @@
+import collections.abc
+import sys
+import typing
+
+if sys.version_info >= (3, 9):
+    MutableMapping = collections.abc.MutableMapping
+else:
+    MutableMapping = typing.MutableMapping