diff --git a/tests/test_services.py b/tests/test_services.py
index 081f1fd..4fc8316 100644
--- a/tests/test_services.py
+++ b/tests/test_services.py
@@ -690,9 +690,11 @@ def __init__(self, cats_controller, service_settings):
 def test_alias_dep_resolving():
     container = arrange_cats_example()
 
-    class BaseClass: ...
+    class BaseClass:
+        pass
 
-    class DerivedClass(BaseClass): ...
+    class DerivedClass(BaseClass):
+        pass
 
     class UsingAliasByType:
         def __init__(self, example: BaseClass):