code: def shutdown(self, shutdown_workers=False):
      self.logger.debug(
          "HBMASTER: shutdown initiated, shutdown_workers = %s"
          % (str(shutdown_workers))
      )
      self.dispatcher.shutdown(shutdown_workers)
      self.dispatcher_thread.join()
  
imports: import os
  import threading
  import time
  import math
  import pdb
  import copy
  import logging
  import numpy
  from hpbandster.core.dispatcher import Dispatcher
  from hpbandster.core.result import Result
  from hpbandster.core.base_iteration import WarmStartIteration
label_desc: Use image node_id 2 for calling the Master obj's underlying member method code with example usage: obj.shutdown(shutdown_workers) without return types