code: def setUp(self):
      self.x = pooling_nd_helper.shuffled_linspace(
          (2, 3, 4, 4), numpy.float32
      )
  
imports: import unittest
  import numpy
  import six
  import chainer
  from chainer.backends import cuda
  from chainer import functions
  from chainer import testing
  from chainer.testing import attr
  from chainer.testing import backend
  from chainer_tests.functions_tests.pooling_tests import pooling_nd_helper
label_desc: Use image node_id 1 for calling the TestMaxPooling2DIndices obj's underlying member method code with example usage: obj.setUp() without return types