code: def check_immutable(self, inputs, backend_config):
      if backend_config.use_cuda:
          inputs = cuda.to_gpu(inputs)
  
      with backend_config:
          dropout = functions.noise.dropout.Dropout(0.5)
          (y1,) = dropout.apply(inputs)
          (y2,) = dropout.apply(inputs)
      testing.assert_allclose(y1.data, y2.data)
  
imports: import unittest
  import numpy
  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
label_desc: Use image node_id 9 for calling the TestDropout obj's underlying member method code with example usage: obj.check_immutable(inputs, backend_config) without return types