code: def setup(self, batched_copy):
      if nccl.get_build_version() < 2000:
          pytest.skip("This test requires NCCL version >= 2.0")
      self.comm = chainermn.create_communicator(
          "pure_nccl", batched_copy=batched_copy
      )
      device = self.comm.intra_rank
      chainer.cuda.get_device_from_id(device).use()
      self.target = ExampleModel()
      self.target.to_device(cupy.cuda.Device())
      self.target.a.W.data[:] = self.comm.rank
      self.target.b.W.data[:] = self.comm.rank + 1
      self.target.c.W.data[:] = self.comm.rank + 2
      self.target.a.W.grad[:] = 0
      self.target.b.W.grad[:] = 0
      self.target.c.W.grad[:] = 0
      self.actual_optimizer = chainer.GradientMethod()
      self.actual_optimizer.create_update_rule = mock.MagicMock
  
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 1 for calling the TestDoubleBufferingOptimizer obj's underlying member method code with example usage: obj.setup(batched_copy) without return types