code: def do_execute(self):
          
          evl = self.input.payload
          if isinstance(evl, Evaluation):
              summary = evl.summary(title=self.resolve_option("title"), complexity=bool(self.resolve_option("complexity")))
              if bool(self.resolve_option("matrix")):
                  summary += "\n" + evl.matrix(title=self.resolve_option("title"))
          else:
              summary = evl.cluster_results
          self._output.append(Token(summary))
          return None
docs: The actual execution of the actor.
  
          :return: None if successful, otherwise error message
          :rtype: str