code: def test_call_cudnn_forward(self):
      with chainer.using_config("use_cudnn", self.use_cudnn):
          with testing.patch(
              "cupy.cudnn.batch_normalization_forward_training_ex"
          ) as func:
              self.forward()
              self.assertEqual(func.called, self.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 3 for calling the TestBatchNormalizationCudnnCall obj's underlying member method code with example usage: obj.test_call_cudnn_forward() without return types