input: 
  def combine_and_reverse(word1: str, word2: str) -> str:
      """ Combine two strings and reverse the result.
      >>> combine_and_reverse("Hello ", "world!")
      '!dlrow olleH'
      >>> combine_and_reverse("Good", "bye!")
      '!eybdooG'
      """
  
output:     combined = word1 + word2
      return combined[::-1]