code: def test_einsum_double_backward_gpu(self):
      self.check_double_backward(
          _tuple_to_gpu(self.inputs),
          cuda.to_gpu(self.g),
          _tuple_to_gpu(self.gg_inputs),
          atol=1e-2,
          rtol=1e-2,
      )
  
imports: import unittest
  import numpy
  import chainer
  from chainer.backends import cuda
  from chainer.functions.math import einsum
  from chainer import gradient_check
  from chainer import testing
  from chainer.testing import attr
  from chainer import utils
label_desc: Use image node_id 8 for calling the TestDiagEinSum obj's underlying member method code with example usage: obj.test_einsum_double_backward_gpu() without return types