code: def testISSendCancel(self):
      size = self.COMM.Get_size()
      rank = self.COMM.Get_rank()
      for smess in messages:
          req = self.COMM.issend(smess, rank, 0)
          self.assertTrue(req)
          flag, _ = req.test()
          self.assertFalse(flag)
          self.assertTrue(req)
          req.cancel()
          self.assertTrue(req)
          status = MPI.Status()
          req.get_status(status)
          if not status.Is_cancelled():
              rmess = self.COMM.recv(None, rank, 0)
              self.assertTrue(req)
              req.wait()
              self.assertFalse(req)
              self.assertEqual(rmess, smess)
          else:
              req.Free()
          self.assertFalse(req)
  
imports: from mpi4py import MPI
  from mpi4py.util import pkl5
  import sys, os
label_desc: Use image node_id 9 for calling the BaseTest obj's underlying member method code with example usage: obj.testISSendCancel() without return types