diff --git a/generic_utils.py b/generic_utils.py
index 7977681f..a99c0456 100644
--- a/generic_utils.py
+++ b/generic_utils.py
@@ -79,7 +79,7 @@ def memoizer(*args, **kwargs):
 #
 ################################################################
 
-class OrderedSet(collections.MutableSet):
+class OrderedSet(collections.abc.MutableSet):
     """
     A set implementations that retains insertion order.  From the receipe
     http://code.activestate.com/recipes/576694/