code: def wait_for_host(self, host):
          
          t = time.time()
          if host in self.times:
              due_time = self.times[host]
              if due_time > t:
                  wait = due_time - t
                  time.sleep(wait)
                  t = time.time()
          wait_time = random.uniform(self.wait_time_min, self.wait_time_max)
          self.times[host] = t + wait_time
docs: Throttle requests to one host.