1. Modify the code to deal with a put option. 2. Acquire some 50ETF option data, and create a figure as before. If possible, investigate the behavior of the implied volatility as the expiry time varies. 1. Modify the code to deal with a put option. 2. Acquire some 50ETF option data, and create a figure as before. If possible, investigate the behavior of the implied volatility as the expiry time varies