diff --git a/fiddy/success.py b/fiddy/success.py
index 1c6fdda..257e72a 100644
--- a/fiddy/success.py
+++ b/fiddy/success.py
@@ -81,8 +81,8 @@ def method(
                 results_by_size[size] = {}
             if result.method_id in results_by_size[size]:
                 raise ValueError(
-                    f'Duplicate, and possibly conflicting, results for method "{result.method_id}" and size "{size}".',
-                    stacklevel=1,
+                    f"Duplicate, and possibly conflicting, results for method "
+                    f'"{result.method_id}" and size "{size}".',
                 )
             results_by_size[size][result.method_id] = result.value