code: def unpack(self, mem):
      ret = numpy.frombuffer(mem, self.dtype, self.size, self.offset)
      ret = ret.reshape(self.shape).copy()
      return ret
  
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 2 for calling the _PackedNdarray obj's underlying member method code with example usage: obj.unpack(mem) and returns: ret