code: def external_ip(self, node_id: str) -> str:
      while True:
          instances = self.acs.describe_instances(
              instance_ids=[node_id]
          )
          if instances is not None:
              assert len(instances)
              instance = instances[0]
              if (
                  instance.get("PublicIpAddress") is not None
                  and instance.get("PublicIpAddress").get("IpAddress")
                  is not None
              ):
                  if (
                      len(
                          instance.get("PublicIpAddress").get(
                              "IpAddress"
                          )
                      )
                      > 0
                  ):
                      return instance.get("PublicIpAddress").get(
                          "IpAddress"
                      )[0]
          cli_logger.error(
              "PublicIpAddress attribute is not exist. %s" % instance
          )
          time.sleep(STOPPING_NODE_DELAY)
  
imports: import logging
  import random
  import threading
  import time
  from collections import defaultdict
  from typing import Any, Dict, List, Optional
  from ray.autoscaler._private.aliyun.config import PENDING, RUNNING, STOPPED, STOPPING, bootstrap_aliyun
  from ray.autoscaler._private.aliyun.utils import AcsClient
  from ray.autoscaler._private.cli_logger import cli_logger
  from ray.autoscaler._private.constants import BOTO_MAX_RETRIES
  from ray.autoscaler._private.log_timer import LogTimer
  from ray.autoscaler.node_provider import NodeProvider
  from ray.autoscaler.tags import TAG_RAY_CLUSTER_NAME, TAG_RAY_LAUNCH_CONFIG, TAG_RAY_NODE_KIND, TAG_RAY_NODE_NAME, TAG_RAY_NODE_STATUS, TAG_RAY_USER_NODE_TYPE
label_desc: Use image node_id 6 for calling the AliyunNodeProvider obj's underlying member method code with example usage: obj.external_ip(node_id) and returns: instance