input: Write a function that takes 2 strings, combines them, and returns the result in reverse order. The function should be called `reverse_and_combine_strings` and should take two string parameters. It should concatenate the two strings and reverse the concatenated result before returning it.
  
  assert reverse_and_combine_strings("Hello ", "world!")==!"dlrow olleH"
  assert reverse_and_combine_strings("Good", " morning")==gninrom dooG"
  assert reverse_and_combine_strings("Python", " is awesome")==emosewa si nohtyP"
  assert reverse_and_combine_strings("", "non-empty")==ymte-non"
  assert reverse_and_combine_strings("Short", "")==trohS"
output: def reverse_and_combine_strings(s1, s2):
      return (s1 + s2)[::-1]