code: def forward_cpu(self, inputs):
      y_expect = _batch_normalization(
          inputs + [self.eps, self.expander]
      )
      return (y_expect,)
  
imports: import unittest
  import warnings
  import numpy
  import six
  import chainer
  from chainer.backends import cuda
  from chainer import functions
  from chainer import gradient_check
  from chainer import testing
  from chainer.testing import attr
  from chainer.testing import backend
label_desc: Use image node_id 2 for calling the TestFixedBatchNormalization obj's underlying member method code with example usage: obj.forward_cpu(inputs) and returns: y_expect