code: def test_mask_iou_invalid(self):
      with self.assertRaises(IndexError):
          mask_iou(self.mask_a, self.mask_b)
  
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 1 for calling the TestMaskIouInvalidShape obj's underlying member method code with example usage: obj.test_mask_iou_invalid() without return types