input: def reverse_words_in_sentence(sentence: str) -> str:
      """ Reverse the order of words in a sentence but keep the order of the characters in each word the same.
      >>> reverse_words_in_sentence("This is a sentence.")
      'sentence. a is This'
      >>> reverse_words_in_sentence("Hello world")
      'world Hello'
      """
output:     words = sentence.split()
      reversed_words = words[::-1]
      return ' '.join(reversed_words)