code: def test_evaluator_name(self):
      self.evaluator.name = "eval"
      mean = self.evaluator()
      # name is used as a prefix
      key = "ap/iou=0.50:0.95/area=all/max_dets=100"
      np.testing.assert_equal(
          mean["eval/main/m{}".format(key)], self.expected_ap
      )
      np.testing.assert_equal(
          mean["eval/main/{}/cls0".format(key)], np.nan
      )
      np.testing.assert_equal(
          mean["eval/main/{}/cls1".format(key)], self.expected_ap
      )
      np.testing.assert_equal(
          mean["eval/main/{}/cls2".format(key)], np.nan
      )
  
imports: import numpy
  import unittest
  import chainer
  from chainer.datasets import TupleDataset
  from chainer.iterators import SerialIterator
  from chainer import testing
  from chainercv.extensions import InstanceSegmentationCOCOEvaluator
  from chainercv.utils.testing import attr
  from chainermn import create_communicator
label_desc: Use image node_id 4 for calling the TestInstanceSegmentationCOCOEvaluator obj's underlying member method code with example usage: obj.test_evaluator_name() without return types