code: def execute(self):
          
          if self.skip:
              return None
  
          result = self.pre_execute()
          if result is None:
              try:
                  result = self.do_execute()
              except Exception as e:
                  result = traceback.format_exc()
                  print(self.full_name + "\n" + result)
          if result is None:
              result = self.post_execute()
          return result
docs: Executes the actor.
  
          :return: None if successful, otherwise error message
          :rtype: str