Exercise 1 (2 points). Write a function, cusum(x, mu), that takes a list of observed temperatures, x, and mean parameter mu as inputs, and then returns a list of the cumulative sum values at each time. Recall that these CuSum values are defined by Assume that S-0, that is, the value at t -1, which is "before"0, is zero. For example S,max 10, S-1-x) x = [20,21,20,19,18,17,15,106,5,4,5,2,5,6,6] mu12 assert cusum(x, m) - [o, 0, 0, 0, 0, 0, 0, 0, 2, 8, 15, 23, 30, 40, 47, 53, 59] In 1: def cusum (x, mu): # YOUR CODE HERE