##list_a = [3, 7, 8,10]
##list_b = [2, 4, 5, 9]
##
def merge(list_a, list_b):
    list_c = [ ]
    while len(list_a) > 0 and len(list_b) > 0:
        if list_a[0] < list_b[0]:
            list_c.append(list_a.pop(0))
        else:
            list_c.append(list_b.pop(0))
    if list_a == [ ]:
        list_c = list_c + list_b
    else:
        list_c = list_c + list_a
    print("Merged list is ", list_c)
    return list_c

def merge_sort(unsorted):
    if len(unsorted) < 2:
        return unsorted
    else:
        middle = len(unsorted)// 2
        front = unsorted[:middle]
        back = unsorted[middle:]
        print("splits are", front, back)
        front = merge_sort(front)
        back = merge_sort(back)
    return merge(front, back)

my_list = [5,4,3,2,1]
merge_sort(my_list)