code: def verify_challenge(uri):
      
      while True:
          try:
              resp = urlopen(uri)
              challenge_status = json.loads(resp.read().decode('utf8'))
          except IOError as e:
              raise ValueError("Error checking challenge: {0} {1}".format(
                  e.code, json.loads(e.read().decode('utf8'))))
          if challenge_status['status'] == "pending":
              time.sleep(2)
          elif challenge_status['status'] == "valid":
              LOGGER.info("Domain verified!")
              break
          else:
              raise ValueError("Domain challenge did not pass: {0}".format(
                  challenge_status))
docs: Loop until our challenge is verified, else fail.