diff --git a/tests/test_iot/test_iot.py b/tests/test_iot/test_iot.py
index 6fe43edc..c3ee4c96 100644
--- a/tests/test_iot/test_iot.py
+++ b/tests/test_iot/test_iot.py
@@ -36,7 +36,8 @@ def generate_thing_group_tree(iot_client, tree_dict, _parent=None):
         subtree_dict = generate_thing_group_tree(
             iot_client=iot_client, tree_dict=tree_dict[group_name], _parent=group_name
         )
-        created_dict = {**created_dict, **subtree_dict}
+        created_dict.update(created_dict)
+        created_dict.update(subtree_dict)
     return created_dict