input: 
  def insertion_sort(list: List[int]) -> List[int]:
      """Implement the insertion sort algorithm.
      >>> insertion_sort([5, 2, 9, 1, 5, 6])
      [1, 2, 5, 5, 6, 9]
      >>> insertion_sort([3, 7, 4, 8, 6])
      [3, 4, 6, 7, 8]
      """
      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
  
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