input: Write a function to take two strings, combine them, and reverse the result. The function should then print the reversed result.
  
  def combine_and_reverse(string1, string2):
      combined = string1 + string2
      result = combined[::-1]
      print(result)
  
  assert combine_and_reverse("Hello ", "world!")  # !dlrow olleH 
  assert combine_and_reverse("1234", "5678")       # 87654321
output: def combine_and_reverse(string1, string2):
      combined = string1 + string2
      result = combined[::-1]
      print(result)