code: def test_mask_iou_gpu(self):
      self.check(
          cuda.to_gpu(self.mask_a),
          cuda.to_gpu(self.mask_b),
          cuda.to_gpu(self.expected),
      )
  
file_path: chainercv/tests/utils_tests/mask_tests/test_mask_iou.py
imports: from __future__ import division
  import unittest
  import numpy
  from chainer.backends import cuda
  from chainer import testing
  from chainer.testing import attr
  from chainercv.utils import mask_iou
label_desc: Use image node_id 3 for calling the TestMaskIou obj's underlying member method code with example usage: obj.test_mask_iou_gpu() without return types