code: def test_reduce(self):
      rank = self.comm.rank
      size = self.comm.size
      for root in range(size):
          msg = rank
          res = self.comm.reduce(sendobj=msg, root=root)
          if self.comm.rank == root:
              self.assertEqual(res, sum(range(size)))
          else:
              self.assertIsNone(res)
  
imports: from mpi4py import MPI
  import unittest
  import sys, os
  from reductions import Intracomm
label_desc: Use image node_id 1 for calling the BaseTest obj's underlying member method code with example usage: obj.test_reduce() without return types