fix: fix type annotation, remove unused parameter, improve import_class errors

rdagent/components/backtesting/results_db.py

@@ -166,7 +166,7 @@ class ResultsDatabase:
         self.conn.commit()
         return c.lastrowid
     
-    def add_loop(self, loop_idx: int, success: int, fail: int, best_ic: float = None, status: str = "completed") -> int:
+    def add_loop(self, loop_idx: int, success: int, fail: int, best_ic: float | None = None, status: str = "completed") -> int:
         c = self.conn.cursor()
         rate = success / (success + fail) if (success + fail) > 0 else 0
         c.execute("""INSERT INTO loop_results (loop_index, factors_success, factors_fail, success_rate, best_ic, status)

rdagent/components/backtesting/vbt_backtest.py

@@ -67,7 +67,6 @@ def _cross_check_with_vbt(
     close: pd.Series,
     position: pd.Series,
     txn_cost: float,
-    manual_total_return: float,
     freq: str,
 ) -> float | None:
     """Run a vectorbt simulation and return its total_return for comparison."""
@@ -264,7 +263,6 @@ def backtest_signal(
             close=close,
             position=position,
             txn_cost=txn_cost,
-            manual_total_return=total_return,
             freq=freq,
         )