Fix imports from collections.abc
diff --git a/Lib/test/test_shelve.py b/Lib/test/test_shelve.py
index 3e73f52..c9c0067 100644
--- a/Lib/test/test_shelve.py
+++ b/Lib/test/test_shelve.py
@@ -2,7 +2,7 @@
 import shelve
 import glob
 from test import support
-from collections import MutableMapping
+from collections.abc import MutableMapping
 from test.test_dbm import dbm_iterator
 
 def L1(s):