docstr: Make sure that IndexRefine can function as a standalone codec 
code: def test_refine(self):
      """Make sure that IndexRefine can function as a standalone codec"""
  
      ds = SyntheticDataset(32, 500, 100, 0)
      index = faiss.index_factory(ds.d, "RQ2x5,Refine(ITQ,LSHt)")
      index.train(ds.get_train())
  
      index1 = index.base_index
      index2 = index.refine_index
  
      codes12 = index.sa_encode(ds.get_database())
      codes1 = index1.sa_encode(ds.get_database())
      codes2 = index2.sa_encode(ds.get_database())
  
      np.testing.assert_array_equal(
          codes12, np.hstack((codes1, codes2))
      )
  
imports: from __future__ import print_function
  import numpy
  import unittest
  import faiss
  from common_faiss_tests import get_dataset_2
  from faiss.contrib.datasets import SyntheticDataset
  from faiss.contrib.inspect_tools import get_additive_quantizer_codebooks
label_desc: Use image node_id 1 for calling the TestRefine obj's underlying member method code with example usage: obj.test_refine() without return types