diff --git a/ext/testlib/helper.py b/ext/testlib/helper.py
index 1cb13f06ec..ed6e325158 100644
--- a/ext/testlib/helper.py
+++ b/ext/testlib/helper.py
@@ -41,7 +41,8 @@
 '''
 Helper classes for writing tests with this test library.
 '''
-from collections import MutableSet, namedtuple
+from collections import namedtuple
+from collections.abc import MutableSet
 
 import difflib
 import errno