Update scenario_engine.py

scenario_engine.py

@@ -1,5 +1,5 @@
 from __future__ import annotations
-from typing import Dict, List, Any, Tuple, Union, Optional
+from typing import Dict, List, Any, Tuple, Optional
 import re, math, json, ast
 import numpy as np
 import pandas as pd
@@ -59,7 +59,6 @@ class ScenarioEngine:
         if isinstance(v, pd.DataFrame): return v
         return None
 
-    # ---------- Plan-first API ----------
     @staticmethod
     def execute_plan(plan: ScenarioPlan, datasets: Dict[str, Any]) -> str:
         sections: List[str] = ["# Scenario Output\n"]
@@ -274,4 +273,3 @@ class ScenarioEngine:
         section.append("\n**Provenance**")
         section.append(f"- Data key: `{t.data_key or 'auto'}`")
         return "\n".join(section)
-