code: def test_einsum_backward_cpu(self):
      if self.dtype == numpy.float16:
          _skip_float16_bug()
      self.check_backward(self.inputs, self.g, atol=1e-2, rtol=5e-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 TestEinSum obj's underlying member method code with example usage: obj.test_einsum_backward_cpu() without return types