code: def _ec2_health_check_waiter(self, node_id: str) -> None:
      # wait for all EC2 instance checks to complete
      try:
          logger.info(
              "Waiting for EC2 instance health checks to complete before "
              "configuring Unified Cloudwatch Agent. This may take a few "
              "minutes..."
          )
          waiter = self.ec2_client.get_waiter("instance_status_ok")
          waiter.wait(InstanceIds=[node_id])
      except botocore.exceptions.WaiterError as e:
          logger.error(
              "Failed while waiting for EC2 instance checks to complete: {}".format(
                  e.message
              )
          )
          raise e
  
imports: import copy
  import hashlib
  import json
  import logging
  import os
  import time
  from enum import Enum
  from typing import Any, Callable, Dict, List, Union
  import botocore
  from ray.autoscaler._private.aws.utils import client_cache, resource_cache
  from ray.autoscaler.tags import NODE_KIND_HEAD, TAG_RAY_CLUSTER_NAME, TAG_RAY_NODE_KIND
label_desc: Use image node_id 3 for calling the CloudwatchHelper obj's underlying member method code with example usage: obj._ec2_health_check_waiter(node_id) without return types