code: def testMessage(self):
      msg = self.MessageType()
      self.assertFalse(msg)
      self.assertEqual(msg, self.MessageType())
      msg = self.MessageType(MPI.MESSAGE_NULL)
      self.assertFalse(msg)
      self.assertEqual(msg, self.MessageType())
      msg = self.MessageType(MPI.MESSAGE_NO_PROC)
      self.assertTrue(msg)
      self.assertEqual(msg, MPI.MESSAGE_NO_PROC)
      self.assertEqual(msg, self.MessageType(MPI.MESSAGE_NO_PROC))
      self.assertNotEqual(msg, MPI.MESSAGE_NULL)
  
imports: from mpi4py import MPI
  from mpi4py.util import pkl5
  import sys, os
label_desc: Use image node_id 22 for calling the BaseTest obj's underlying member method code with example usage: obj.testMessage() without return types