code: def _run_test_get_set(self, errhandler):
      mpiobj = self.mpiobj
      errhdl_1 = mpiobj.Get_errhandler()
      self.assertNotEqual(errhdl_1, MPI.ERRHANDLER_NULL)
      mpiobj.Set_errhandler(errhandler)
      errhdl_2 = mpiobj.Get_errhandler()
      self.assertEqual(errhdl_2, errhandler)
      errhdl_2.Free()
      self.assertEqual(errhdl_2, MPI.ERRHANDLER_NULL)
      mpiobj.Set_errhandler(errhdl_1)
      errhdl_1.Free()
      self.assertEqual(errhdl_1, MPI.ERRHANDLER_NULL)
  
imports: from mpi4py import MPI
  import mpiunittest
label_desc: Use image node_id 4 for calling the BaseTestErrhandler obj's underlying member method code with example usage: obj._run_test_get_set(errhandler) without return types