code: def _stop_worker(self, worker_id, blocking=True):
      op = (
          self.compute.instances()
          .delete(
              project=self.projectid, zone=self.zone, instance=worker_id
          )
          .execute()
      )
  
      if blocking:
          self._wait_for_operation(op["name"])
      else:
          return op["name"]
  
imports: import os
  import time
  import googleapiclient.discovery
  import uuid
  import math
  import json
  from studio import git_util
  from studio.util import logs
  from studio.util.gpu_util import memstr2int
  from .cloud_worker_util import insert_user_startup_script
label_desc: Use image node_id 5 for calling the GCloudWorkerManager obj's underlying member method code with example usage: obj._stop_worker(worker_id, blocking) and returns: op