Given an integer array arr and an integer k, modify the array by repeating it k times. For example, if arr = [1, 2] and k = 3 then the modified array will be [1, 2, 1, 2, 1, 2]. Return the maximum sub-array sum in the modified array. Note that the length of the sub-array can be 0 and its sum in that case is 0. As the answer can be very large, return the answer modulo 109 + 7. Example 1: Input: arr = [1,2], k = 3 Output: 9 Example 2: Input: arr = [1,-2,1], k = 5 Output: 2 Example 3: Input: arr = [-1,-2], k = 7 Output: 0 Constraints: 1 <= arr.length <= 105 1 <= k <= 105 -104 <= arr[i] <= 104