code: def testCloneFree(self):
      comm = self.COMM.Clone()
      comm.Free()
      self.assertEqual(comm, MPI.COMM_NULL)
  
imports: from mpi4py import MPI
  import mpiunittest
label_desc: Use image node_id 5 for calling the BaseTestComm obj's underlying member method code with example usage: obj.testCloneFree() without return types