input: 
  def reverse_words(string: str) -> str:
      """ Reverse the order of words in a sentence but keep the order of the characters in each word the same.
      >>> reverse_words('This is a sentence.')
      'sentence. a is This'
      >>> reverse_words('Hello world')
      'world Hello'
      """
      words = string.split(" ")
      reversed_words = []
      for word in words:
          reversed_words.insert(0, word)
      return ' '.join(reversed_words)
  
output:     words = string.split(" ")
      reversed_words = []
      for word in words:
          reversed_words.insert(0, word)
      return ' '.join(reversed_words)