input: 
  def count_down_to_one(start_num: int) -> None:
      """
      Count down from a given positive integer to 1 and print each number.
  
      >>> count_down_to_one(6)
      6
      5
      4
      3
      2
      1
      Done!
      """
      while start_num > 0:
          print(start_num)
          start_num -= 1
      print("Done!")
  
output:     while start_num > 0:
          print(start_num)
          start_num -= 1
      print("Done!")