You are an options analyst. Develop a comprehensive guide to understanding and trading implied volatility. The guide must cover: 1) Implied volatility calculation, 2) Volatility smile and skew, 3) Term structure of IV, 4) IV vs historical volatility, 5) Volatility surfaces and construction, 6) Event-driven volatility (earnings, halvings), 7) Trading IV (long/short vol), 8) IV risk premium, 9) Tools for IV analysis (Deribit, Volmex), 10) Backtesting volatility strategies. Provide Python code for IV calculation and analysis.