code: def setUp(self):
      N = 3
      n_channels = 3
      self.x = pooling_nd_helper.shuffled_linspace(
          (N, n_channels, 12, 8), self.dtype
      )
      self.rois = numpy.array(
          [[1, 1, 7, 7], [2, 6, 12, 8], [1, 3, 11, 6], [3, 3, 4, 4]],
          dtype=self.dtype,
      )
      self.roi_indices = numpy.array([0, 2, 1, 0], dtype=numpy.int32)
      n_rois = self.rois.shape[0]
      outsize = _pair(self.outsize)
      self.gy = numpy.random.uniform(
          -1, 1, (n_rois, n_channels, outsize[0], outsize[1])
      ).astype(self.dtype)
      if self.dtype == numpy.float16:
          self.check_backward_options = {
              "dtype": numpy.float64,
              "atol": 1e-2,
              "rtol": 1e-2,
          }
      else:
          self.check_backward_options = {"atol": 1e-3, "rtol": 1e-2}
  
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
  from chainer_tests.functions_tests.pooling_tests import pooling_nd_helper
label_desc: Use image node_id 1 for calling the TestROIMaxPooling2D obj's underlying member method code with example usage: obj.setUp() without return types