code: def testCartMap(self):
      comm = self.COMM
      size = comm.Get_size()
      for ndim in (1, 2, 3, 4, 5):
          for periods in (None, True, False):
              dims = MPI.Compute_dims(size, ndim)
              topo = comm.Create_cart(dims, periods, reorder=True)
              rank = comm.Cart_map(dims, periods)
              self.assertEqual(topo.Get_rank(), rank)
              topo.Free()
  
imports: from mpi4py import MPI
  import mpiunittest
label_desc: Use image node_id 7 for calling the BaseTestTopo obj's underlying member method code with example usage: obj.testCartMap() without return types