code: def testConstructorDistGraphcomm(self):
      comm = MPI.COMM_SELF
      try:
          distgraph = comm.Create_dist_graph([], [], [])
      except NotImplementedError:
          self.skipTest("mpi-comm-create_dist_graph")
      with self.assertRaises(TypeError):
          MPI.Cartcomm(distgraph)
      with self.assertRaises(TypeError):
          MPI.Graphcomm(distgraph)
      distgraph.Free()
      with self.assertRaises(ValueError):
          comm.Create_dist_graph_adjacent(
              [0],
              [0],
              MPI.WEIGHTS_EMPTY,
              MPI.WEIGHTS_EMPTY,
          )
  
imports: from mpi4py import MPI
  import mpiunittest
label_desc: Use image node_id 4 for calling the TestTopoConstructor obj's underlying member method code with example usage: obj.testConstructorDistGraphcomm() without return types