diff --git a/Lib/test/test_unittest/testmock/testhelpers.py b/Lib/test/test_unittest/testmock/testhelpers.py
index b8beeb34e72023..f260769eb8c35e 100644
--- a/Lib/test/test_unittest/testmock/testhelpers.py
+++ b/Lib/test/test_unittest/testmock/testhelpers.py
@@ -1096,6 +1096,7 @@ class WithNonFields:
             a: ClassVar[int]
             b: InitVar[int]
 
+        msg = "Mock object has no attribute"
         for mock in [
             create_autospec(WithNonFields, instance=True),
             create_autospec(WithNonFields(1)),