def mergeSort(A):
    new_arr = A[:]
    # print("Call sort on ",A)
    if len(new_arr) > 1:
        mid = len(new_arr) // 2
        leftA = new_arr[:mid]  # divide into 2 sub lists
        rightA = new_arr[mid:]

        mergeSort(leftA)  # conquer (recursive call)
        mergeSort(rightA)  # conquer (recursive call)

        merge(leftA, rightA, new_arr)  # combine (merge the 2 sub lists)

    return new_arr