diff --git a/docs/usage.md b/docs/usage.md
index 712e458..32e45a3 100644
--- a/docs/usage.md
+++ b/docs/usage.md
@@ -372,7 +372,7 @@ start = datetime.date(2022, 1, 4)
 end = datetime.date(2023, 1,1)
 
 sma = SMAStrategy(sec, url=cfg.backtest.url, is_backtest=True, start=start, end=end, frame_type=FrameType.DAY, warmup_period=10)
-await sma.backtest(portfolio=[sec], stop_on_error=False)
+await sma.backtest(prefetch_stocks=[sec], stop_on_error=False)
 await sma.plot_metrics(sma.indicators)
 
 ```