diff --git a/.github/workflows/main.yaml b/.github/workflows/main.yaml
index b9fe5e21e..2e4a7001e 100644
--- a/.github/workflows/main.yaml
+++ b/.github/workflows/main.yaml
@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [ '3.9' ]
+        python-version: [ '3.9', '3.10' ]
     steps:
       - uses: actions/checkout@v2
       - name: Set up Python ${{ matrix.python-version }}
@@ -32,7 +32,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [ '3.9' ]
+        python-version: [ '3.9', '3.10' ]
 
     steps:
 
diff --git a/src/oaklib/utilities/mapping/cross_ontology_diffs.py b/src/oaklib/utilities/mapping/cross_ontology_diffs.py
index 0a0d455ee..4ece8c268 100644
--- a/src/oaklib/utilities/mapping/cross_ontology_diffs.py
+++ b/src/oaklib/utilities/mapping/cross_ontology_diffs.py
@@ -1,5 +1,6 @@
 import logging
-from collections import Iterator, defaultdict
+from collections import defaultdict
+from collections.abc import Iterator
 from copy import deepcopy
 from typing import Dict, List, Optional, Tuple