input: Write a function to take a positive integer as input and use a while loop to output the numbers counting down to 1. Then print "Done!" at the end.
  def countdown_from_num(num):
      while num > 0:
          print(num)
          num -= 1
      print("Done!")
  
  assert countdown_from_num(6) == None
  assert countdown_from_num(3) == None
  assert countdown_from_num(1) == None
  assert countdown_from_num(5) == None
  assert countdown_from_num(2) == None
output: def countdown_from_num(num):
      while num > 0:
          print(num)
          num -= 1
      print("Done!")