code: def setUp(self):
      self.comm = create_communicator("naive")
  
      batchsize_per_process = 5
      batchsize = batchsize_per_process * self.comm.size
      if self.comm.rank == 0:
          masks = [
              np.random.uniform(size=(5, 32, 48)) > 0.5
              for _ in range(10)
          ]
          labels = [
              np.random.choice(np.arange(3, dtype=np.int32), size=(5,))
              for _ in range(10)
          ]
      else:
          masks = None
          labels = None
      initial_count = self.comm.rank * batchsize_per_process
  
      masks = self.comm.bcast_obj(masks)
      labels = self.comm.bcast_obj(labels)
      self.masks = masks
      self.labels = labels
  
      self.dataset = TupleDataset(
          np.random.uniform(size=(10, 3, 32, 48)), masks, labels
      )
      self.initial_count = initial_count
      self.batchsize = batchsize
  
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 1 for calling the TestInstanceSegmentationCOCOEvaluatorMPI obj's underlying member method code with example usage: obj.setUp() without return types