code: def do_execute(self):
          
  
          result = None
          self._stopped = False
          self._stopping = False
  
          for actor in self.owner.actors:
              if self.is_stopping() or self.is_stopped():
                  break
              actor.input = self.owner.input
              result = actor.execute()
              if result is not None:
                  break
  
          return result
docs: Actual execution of the director.
  
          :return: None if successful, otherwise error message
          :rtype: str