code: def test_update_with_batched_copy(self):
      self.check_update(True)
  
imports: import chainer
  from chainer.backends.cuda import cupy
  import chainer.testing
  import chainer.testing.attr
  import chainermn
  from chainermn import nccl
  import mock
  import numpy
  import pytest
  import unittest
label_desc: Use image node_id 4 for calling the TestDoubleBufferingOptimizer obj's underlying member method code with example usage: obj.test_update_with_batched_copy() without return types