input: def insertion_sort(list):
      """ Implement an insertion sort algorithm that sorts a given list of elements in ascending order.
      >>> insertion_sort([4, 2, 1, 7, 5])
      [1, 2, 4, 5, 7]
      >>> insertion_sort([3, 3, 3])
      [3, 3, 3]
      """
output:     for i in range(1, len(list)):
          key = list[i]
          j = i - 1
          while j >= 0 and key < list[j]:
              list[j + 1] = list[j]
              j -= 1
          list[j + 1] = key
      return list