code: def checkFortran(self, oldcomm):
      fint = oldcomm.py2f()
      newcomm = MPI.Comm.f2py(fint)
      self.assertEqual(newcomm, oldcomm)
      self.assertEqual(type(newcomm), type(oldcomm))
  
imports: from mpi4py import MPI
  import mpiunittest
label_desc: Use image node_id 1 for calling the BaseTestTopo obj's underlying member method code with example usage: obj.checkFortran(oldcomm) without return types