code: def _run(self):
      # The entry routine of the prefetch thread.
  
      alive = True
      try:
          while alive:
              if self._terminating:
                  break
              alive = self._task()
      finally:
          self._pool.close()
          self._pool.join()
  
imports: from __future__ import division
  import datetime
  import multiprocessing
  from multiprocessing import sharedctypes
  import signal
  import sys
  import threading
  import warnings
  import numpy
  import six
  from chainer.dataset import iterator
  from chainer.iterators import _statemachine
  from chainer.iterators.order_samplers import ShuffleOrderSampler
label_desc: Use image node_id 8 for calling the _PrefetchLoop obj's underlying member method code with example usage: obj._run() without return types