code: def test_forward(self, backend_config):
      self.check_forward(self.inputs, False, backend_config)
  
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 4 for calling the TestFixedBatchNormalization obj's underlying member method code with example usage: obj.test_forward(backend_config) without return types