input: from typing import List
  
  def insertion_sort(arr: List[int]):
      """Sort a list of n distinct integers using the insertion sort algorithm.
      >>> insertion_sort([12, 11, 13, 5, 6])
      [5, 6, 11, 12, 13]
      >>> insertion_sort([5, 4, 3, 2, 1])
      [1, 2, 3, 4, 5]
      """
      for i in range(1, len(arr)): 
          key = arr[i] 
          j = i - 1
          while j >= 0 and key < arr[j]: 
              arr[j + 1] = arr[j] 
              j -= 1
          arr[j + 1] = key
output:     return arr