问题 I have the below code: import yfinance as yf import pandas as pd import datetime as dt end=dt.datetime.today() start=end-dt.timedelta(59) tickers=['WBA', 'HD'] ohlcv={} df=pd.DataFrame df = yf.download(tickers,group_by=tickers,start=start,end=end,interval='5m') df['h-l']=abs(df.High-df.Low) df['h-pc']=abs (df.High-df['Adj Close'].shift(1)) df['l-pc']=abs(df.Low-df['Adj Close'].shift(1)) df['tr']=df[['h-l','h-pc','l-pc']].max(axis=1) df['atr']=df['tr'].rolling(window=n, min_periods=n).mean()