code: def testNewBytes(self):
      buffer = MPI.buffer
      obj = b"abc"
      buf = buffer(obj)
      self.assertEqual(buf.obj, obj)
      self.assertEqual(buf.nbytes, len(obj))
      self.assertIs(buf.readonly, True)
      with self.assertRaises(TypeError):
          buf[:] = 0
  
file_path: mpi4py/test/test_buffer.py
imports: from mpi4py import MPI
  import mpiunittest
label_desc: Use image node_id 3 for calling the TestBuffer obj's underlying member method code with example usage: obj.testNewBytes() without return types