Update grader.py

grader.py

@@ -394,4 +394,4 @@ def calculate_overall_score(task_scores: list) -> float:
     raw_avg = sum(task_scores) / len(task_scores)
     # Normalise from the per-step range (R_BREACH … R_PERFECT) → (0, 1)
     normalised = (raw_avg - R_BREACH) / (R_PERFECT - R_BREACH)
-    return safe_score(max(0.0, min(1.0, normalised)))
+    return safe_score(max(0.0, min(1.0, normalised)))