code: def testManyISSendAndRecv(self):
      size = self.COMM.Get_size()
      rank = self.COMM.Get_rank()
      for smess in messages:
          reqs = []
          for k in range(6):
              r = self.COMM.issend(smess, rank, 0)
              reqs.append(r)
          flag = MPI.Request.Testall(reqs)
          self.assertFalse(flag)
          for k in range(3):
              rmess = self.COMM.recv(None, rank, 0)
              self.assertEqual(rmess, smess)
          flag = MPI.Request.Testall(reqs)
          self.assertFalse(flag)
          index, flag = MPI.Request.Testany(reqs)
          if flag:
              self.assertEqual(index, 0)
          indices = MPI.Request.Testsome(reqs)
          if indices is not None:
              target = [0, 1, 2]
              if flag:
                  del target[0]
              for index in indices:
                  self.assertIn(index, target)
          for k in range(3):
              flag = MPI.Request.Testall(reqs)
              self.assertFalse(flag)
              rmess = self.COMM.recv(None, rank, 0)
              self.assertEqual(rmess, smess)
          flag = False
          for k in range(2):
              flag |= MPI.Request.Testall(reqs)
          if unittest.is_mpi("intelmpi") and sys.platform == "win32":
              flag |= MPI.Request.Waitall(reqs)
          self.assertTrue(flag)
  
imports: from mpi4py import MPI
  import mpiunittest
  import threading
  import warnings
  import sys
label_desc: Use image node_id 6 for calling the BaseTestP2PObj obj's underlying member method code with example usage: obj.testManyISSendAndRecv() without return types