code: def check_forward(self, x_data):
      x = chainer.Variable(x_data)
      # Make the batch normalization to be the identity function.
      self.l.bn.avg_var[:] = 1
      self.l.bn.avg_mean[:] = 0
      with chainer.using_config("train", False):
          y = self.l(x)
  
      self.assertIsInstance(y, chainer.Variable)
      self.assertIsInstance(y.array, self.l.xp.ndarray)
  
      np.testing.assert_almost_equal(
          cuda.to_cpu(y.array),
          np.maximum(cuda.to_cpu(x_data), 0),
          decimal=4,
      )
  
imports: import unittest
  import numpy
  import chainer
  from chainer.backends import cuda
  from chainer.functions import relu
  from chainer import testing
  from chainermn import create_communicator
  from chainercv.links import Conv2DBNActiv
  from chainercv.utils.testing import attr
label_desc: Use image node_id 2 for calling the TestConv2DMultiNodeBNActiv obj's underlying member method code with example usage: obj.check_forward(x_data) without return types