input: def reverse_sentence_order(sentence: str) -> str:
      """ Reverses the order of words in a given sentence while keeping the order of characters in each word unchanged.
      >>> reverse_sentence_order("This is a sentence.")
      'sentence. a is This'
      >>> reverse_sentence_order("Hello world")
      'world Hello'
      """
output:     words = sentence.split()
      reversed_words = words[::-1]
      return ' '.join(reversed_words)