code: def test_call_cudnn_forward(self):
      default_func = cuda.cupy.cudnn.activation_forward
      with chainer.using_config("use_cudnn", self.use_cudnn):
          with testing.patch("cupy.cudnn.activation_forward") as func:
              func.side_effect = default_func
              self.forward()
              self.assertEqual(func.called, self.expect)
  
imports: import unittest
  import numpy
  import chainer
  from chainer.backends import cuda
  from chainer import functions
  from chainer import testing
  from chainer.testing import attr
  from chainer import utils
label_desc: Use image node_id 3 for calling the TestSigmoidCudnnCall obj's underlying member method code with example usage: obj.test_call_cudnn_forward() without return types