code: def test_getIoUMissing(self):
      matrix = np.asarray([[1, 0, 0], [0, 1, 0], [0, 0, 0]])
      confusion = ConfusionMatrix.create_from_matrix(matrix)
      iou, mask = confusion.get_intersection_union_per_class()
      self.assertAlmostEqual(iou[0], 1)
      self.assertAlmostEqual(iou[1], 1)
      self.assertAlmostEqual(iou[2], 0)
      npt.assert_array_equal(mask, np.array([True, True, False]))
  
file_path: torch-points3d/test/test_confusionMatrix.py
imports: import os
  import sys
  import numpy
  import unittest
  import tempfile
  import h5py
  import numpy.testing
  import numpy.matlib
  from torch_points3d.metrics.confusion_matrix import ConfusionMatrix
label_desc: Use image node_id 4 for calling the TestConfusionMatrix obj's underlying member method code with example usage: obj.test_getIoUMissing() without return types