code: def load_joke(service_num=1):
      
      result = {
        1 : ronswanson.get_joke(),
        2 : chucknorris.get_joke(),
        3 : catfacts.get_joke(),
        4 : dadjokes.get_joke(),
      }.get(service_num)
  
      return result
docs: Pulls the joke from the service based on the argument.
      
      It is expected that all services used will return a string
      when successful or None otherwise.