code: def test_backward_gpu_without_cudnn(self):
      self.link.use_cudnn = False
      self.link(numpy.zeros(self.shape, dtype="f"))
      self.test_backward_gpu()
  
imports: import unittest
  import numpy
  import chainer
  from chainer.backends import cuda
  from chainer import gradient_check
  from chainer import links
  from chainer import testing
  from chainer.testing import attr
  from chainer.testing import condition
  from chainer.utils import type_check
label_desc: Use image node_id 10 for calling the LayerNormalizationTest obj's underlying member method code with example usage: obj.test_backward_gpu_without_cudnn() without return types