code: def check_actors(self, actors):
          
          super(Sequence, self).check_actors(actors)
          actor = self.first_active
          if (actor is not None) and not isinstance(actor, InputConsumer):
              raise Exception("First active actor does not accept input: " + actor.full_name)
docs: Performs checks on the actors that are to be used. Raises an exception if invalid setup.
  
          :param actors: the actors to check
          :type actors: list