input: 
  def reverse_words(input_string: str) -> str:
      """ Reverses the order of words in a given string.
      Example:
      >>> reverse_words("hello world")
      'world hello'
      >>> reverse_words("Python is fun")
      'fun is Python'
      >>> reverse_words("singleword")
      'singleword'
      """
      return " ".join(input_string.split()[::-1])
  
output:     words = input_string.split()
      reversed_words = words[::-1]
      return " ".join(reversed_words)