diff --git a/python/packages/core/agent_framework/_evaluation.py b/python/packages/core/agent_framework/_evaluation.py
index cc334167eb..64fab0eacb 100644
--- a/python/packages/core/agent_framework/_evaluation.py
+++ b/python/packages/core/agent_framework/_evaluation.py
@@ -1733,7 +1733,10 @@ async def evaluate_workflow(
         raise ValueError("Provide either 'workflow_result' or 'queries'.")
 
     if expected_output is not None and queries is None:
-        raise ValueError("Provide 'queries' when using 'expected_output'; 'expected_output' is not supported with 'workflow_result' only.")
+        raise ValueError(
+            "Provide 'queries' when using 'expected_output';"
+            " 'expected_output' is not supported with 'workflow_result' only."
+        )
     if expected_output is not None and queries is not None and len(expected_output) != len(queries):
         raise ValueError(f"Got {len(queries)} queries but {len(expected_output)} expected_output values.")