我在用Python写一个脚本，用yfinance获取各类信息。当我拉取个股的期权链信息时，代码是正常工作的，但用SPY作为代码时就出错了。

stock.info['currentPrice'] 这个字段在SPY（以及其他ETF）上似乎会出问题。我查了文档，但没找到SPY这类ETF的当前价格有不同命名的说明。

import yfinance as yf
import pandas as pd

def get_option_chain(ticker, date=None):
    """
    Fetch option chain data for a specific security from Yahoo Finance

    Parameters:
    ticker (str): Stock ticker symbol (e.g., 'AAPL', 'MSFT')
    date (str): Optional expiration date in 'YYYY-MM-DD' format

    Returns:
    tuple: (calls_df, puts_df) DataFrames containing calls and puts data
    """
    try:
        # Create ticker object
        stock = yf.Ticker(ticker)

        # Get option chain
        if date:
            opt = stock.option_chain(date)
        else:
            # Get the first available expiration date if none specified
            expirations = stock.options
            if not expirations:
                raise ValueError(f"No options available for {ticker}")
            opt = stock.option_chain(expirations[0])

        # Extract calls and puts
        calls = opt.calls
        puts = opt.puts

        # Add some useful calculated columns
        current_price = stock.info['currentPrice']
        calls['moneyness'] = (current_price / calls['strike']).round(3)
        puts['moneyness'] = (current_price / puts['strike']).round(3)

        # Format the output
        for df in [calls, puts]:
            df['impliedVolatility'] = (df['impliedVolatility'] * 100).round(2)
            df['lastPrice'] = df['lastPrice'].round(2)
            df['bid'] = df['bid'].round(2)
            df['ask'] = df['ask'].round(2)

        return calls, puts

    except Exception as e:
        print(f"Error fetching option chain: {str(e)}")
        return None, None

def main():
    # Example usage
    ticker = 'SPY'  # Change this to your desired ticker

    # Get all available expiration dates
    stock = yf.Ticker(ticker)
    expiration_dates = stock.options

    print(f"\nAvailable expiration dates for {ticker}:")
    for date in expiration_dates:
        print(date)

    # Loop through each expiration date and get the option chain
    all_calls = []
    all_puts = []
    for date in expiration_dates:
        calls, puts = get_option_chain(ticker, date)
        if calls is not None and puts is not None:
            calls['expirationDate'] = date  # Add expiration date to calls DataFrame
            puts['expirationDate'] = date  # Add expiration date to puts DataFrame
            all_calls.append(calls)
            all_puts.append(puts)

    # Concatenate all calls and puts DataFrames
    all_calls_df = pd.concat(all_calls, ignore_index=True)
    all_puts_df = pd.concat(all_puts, ignore_index=True)

    # Display some basic information or save to CSV
    print(f"\nAll Calls for {ticker}:")
    print(all_calls_df[['strike', 'lastPrice', 'bid', 'ask', 'volume', 'impliedVolatility', 'moneyness', 'expirationDate']].head())

    print(f"\nAll Puts for {ticker}:")
    print(all_puts_df[['strike', 'lastPrice', 'bid', 'ask', 'volume', 'impliedVolatility', 'moneyness', 'expirationDate']].head())

    # Optionally save to CSV
    all_calls_df.to_csv(f"{ticker}_all_calls.csv", index=False)
    all_puts_df.to_csv(f"{ticker}_all_puts.csv", index=False)

if __name__ == "__main__":
    main()

错误提示：KeyError: 'currentPrice'（使用SPY等ETF时触发该错误，个股则可正常获取该字段值）

备注：内容来源于stack exchange，提问作者sawooooooo