2. Reference drawChart () function, please design a averagePrices function, with three parameters, stockID, startDate and endDate, returns a DataFrame, contain code for stockID shares from the date of the date of startDate and endDate closing price, average price of 3, 6, 9 closing quotation price and closing price data, hint: use the pandas in rolling function can help you to realize, (20%)
3. Three average strategy is a very classic trend tracking strategy, its concrete expression as follows, all line up quickly through the medium of averages when they buy, and when fast average down through the slow line when they sell, if we use 3 - day moving average as a quick line, 6 daily average lines as a medium of averages, 9 - day moving average as slow average, customize a stock, please find out on January 1, 2019 so far all the buying date and selling date,