code: def do_execute(self):
          
          for i in range(
                  int(self.resolve_option("min")),
                  int(self.resolve_option("max")) + 1,
                  int(self.resolve_option("step"))):
              self._output.append(Token(i))
          return None
docs: The actual execution of the actor.
  
          :return: None if successful, otherwise error message
          :rtype: str