code: def fetch(self, url):
          '''Return (expiration, Agent) for the robots.txt at the provided URL.'''
          robots = Robots.fetch(
              url, ttl_policy=self.ttl_policy, *self.args, **self.kwargs)
          return (robots.expires, robots.agent(self.agent)f fetch(self, url):
          '''Return (expiration, Agent) for the robots.txt at the provided URL.'''
          robots = Robots.fetch(
              url, ttl_policy=self.ttl_policy, *self.args, **self.kwargs)
          return (robots.expires, robots.agent(self.agent))
docs: Return (expiration, Agent) for the robots.txt at the provided URL.