text: sell_price = new_df['close'][i]            if sell_price <= buy_price * (1 - stop_loss):                new_df['pnl'][i] = -stop_loss            elif sell_price >= buy_price * (1 + profit_target):                new_df['pnl'][i] = profit_target            else:                new_df['pnl'][i] = (sell_price - buy_price) / buy_price    ```        This will create a new column called 'pnl' in the DataFrame that indicates the profit or loss for each trade based on the buy and sell signals and the defined stop loss and profit target. The stop loss and profit target are calculated based on the stop_loss_percent and profit_target_percent variables, respectively. The buy and sell prices are stored in the buy_price and sell_price variables, respectively. If the sell price is less than or equal to the stop loss, the profit or loss is set to -stop_loss. If the sell price is greater than or equal to the profit target, the profit or loss is set to profit_target. Otherwise, the profit or loss is calculated as (sell_price - buy_price) / buy_price. Next request.            AI User (Stock Trader):        Instruction: Calculate the total profit or loss for all trades.    Input: None.            AI Assistant (Python Programmer):        Solution: We can calculate the total profit or loss for all trades