code: def testGetSetErrhandler(self):
      for ERRHANDLER in [
          MPI.ERRORS_ARE_FATAL,
          MPI.ERRORS_RETURN,
          MPI.ERRORS_ARE_FATAL,
          MPI.ERRORS_RETURN,
      ]:
          errhdl_1 = self.WIN.Get_errhandler()
          self.assertNotEqual(errhdl_1, MPI.ERRHANDLER_NULL)
          self.WIN.Set_errhandler(ERRHANDLER)
          errhdl_2 = self.WIN.Get_errhandler()
          self.assertEqual(errhdl_2, ERRHANDLER)
          errhdl_2.Free()
          self.assertEqual(errhdl_2, MPI.ERRHANDLER_NULL)
          self.WIN.Set_errhandler(errhdl_1)
          errhdl_1.Free()
          self.assertEqual(errhdl_1, MPI.ERRHANDLER_NULL)
  
imports: from mpi4py import MPI
  import mpiunittest
  import sys
label_desc: Use image node_id 6 for calling the BaseTestWin obj's underlying member method code with example usage: obj.testGetSetErrhandler() without return types