diff --git a/mypy.bash b/mypy.bash
index 1f96478c0..d85d639c2 100755
--- a/mypy.bash
+++ b/mypy.bash
@@ -23,4 +23,4 @@ utils="../SpiNNUtils/spinn_utilities"
 machine="../SpiNNMachine/spinn_machine"
 man="../SpiNNMan/spinnman"
 
-mypy $utils $machine $man pacman
+mypy --python-version 3.8 $utils $machine $man pacman
diff --git a/unittests/model_tests/routing_table_tests/test_routing_tables_model.py b/unittests/model_tests/routing_table_tests/test_routing_tables_model.py
index 115202211..e113b5c11 100644
--- a/unittests/model_tests/routing_table_tests/test_routing_tables_model.py
+++ b/unittests/model_tests/routing_table_tests/test_routing_tables_model.py
@@ -144,6 +144,7 @@ def test_new_multicast_routing_tables(self):
         mrt.append(t1)
         mrt.append(t2)
         tables = MulticastRoutingTables(mrt)
+        self.assertEqual(len(tables), len(list(tables)))
         retrieved_tables = tables.routing_tables
         self.assertEqual(len(retrieved_tables), len(mrt))
         self.assertEqual(len(tables), len(mrt))