Write a function called median score(di) that takes a dictionary as an argument. the keys of the dictionary are strings representing student names and the values are lists of integers between 0 and 100 inclusive representing grades. The function should return a new dictionary where the keys are the same as in di and the values are the median of the grades for each student. For example, if grades = {"Caleb" : [75, 89, 92, 66], "LaToya" : [92, 97, 90, 97], "Jon" : [92, 98, 60, 84], "Mike" : [90, 92, 97, 91]}