create a function that accepts an array a of integers and return the maximum skipped subarray contiguous sum. The idea of a skipped subarray is like skip counting kids do in elementary school: Skip counting by 1 is simply counting: 0, 1, 2, 3,... Skip counting by 2 is counting: 0,2, 4, 6,... Skip counting by 3 is counting: 0,3,6,9,... Etc... Notice that we always start at 0. More formally, a skipped subarray with skip k is a subarray of a given by a[0], a[k], a[2k],..., a[nk] for some n. The maximum skipped subarray contiguous sum is defined as the maximum sum of any contiguous subarray of the possible skipped subarrays of a. For example it could be a[6] + a[9] + a[12], which is part of the skipped subarray a[0], a[3], a[6], a[9], a[12],... Your function has the following signature: def msk (a): return maxsum It returns the maximum sum. This sum is deemed to be zero for empty subarrays. Hence if the array only contains negative numbers, your function should return 0. There are multiple solutions, with various runtime and space requirements. You will get full marks ony for the optimal solution requiring no additional space.