Exercise $9.$ The Python function Sharpe$\_$Ratio uses a "helper" function data$\_$func to calculate the ${}_a,{}_b,R_a,R_b$ and $$ from a data set of $20$ stocks. This data is then used by the sharpe$\_$Ratio function to calculate $x$ and $y(x_{{?}_o\text{p}\text{t}\text{i}\text{m}\text{a}\text{l}\text{a}\text{n}\text{d}}$ y$\_$optimal$)$ and return the optimal Sharpe Ratio s$\_$max. Finish sharpe$\_$Ratio by filling in the missing line of code below. Hint: How did you find the amount to invest in stock B in the previous exercise?