code: def _test_barrier(
      self,
      comm_rank=None,
      comm_size=None,
      tmpdir=None,
  ):
      store_handler, common_world = self.create_common_world(
          comm_rank=comm_rank, comm_size=comm_size, tmpdir=tmpdir
      )
  
      net = core.Net("barrier")
      net.Barrier([common_world], [], engine=op_engine)
  
      workspace.CreateNet(net)
      workspace.RunNet(net.Name())
  
      # Run the net a few more times to check the operator
      # works not just the first time it's called
      for _tmp in range(4):
          workspace.RunNet(net.Name())
  
imports: from hypothesis import given, settings
  import hypothesis.strategies
  from multiprocessing import Process, Queue
  import numpy
  import os
  import pickle
  import tempfile
  import shutil
  from caffe2.python import core, workspace, dyndep
  import caffe2.python.hypothesis_test_util
  from gloo.python import IoError
label_desc: Use image node_id 15 for calling the TestCase obj's underlying member method code with example usage: obj._test_barrier(comm_rank, comm_size, tmpdir) without return types