code: def test_consistency_regression_backward(self, backend_config):
      ndim = len(self.dims)
      if ndim == 2:
          self.check_backward_consistency_regression(backend_config)
  
imports: import itertools
  import unittest
  import numpy
  import six
  import chainer
  from chainer import backend
  from chainer import functions
  from chainer import testing
  from chainer.utils import conv
  from chainer.utils import type_check
label_desc: Use image node_id 8 for calling the TestUnpoolingND obj's underlying member method code with example usage: obj.test_consistency_regression_backward(backend_config) without return types