code: def test_IndexPQ_refined(self):
      q = faiss.IndexPQ(d, M, nbits_per_index)
      res = ev.launch("PQ non-refined", q)
      e = ev.evalres(res)
      q.reset()
  
      rq = faiss.IndexRefineFlat(q)
      res = ev.launch("PQ refined", rq)
      e2 = ev.evalres(res)
      assert e2[10] >= e[10]
      rq.k_factor = 4
  
      res = ev.launch("PQ refined*4", rq)
      e3 = ev.evalres(res)
      assert e3[10] >= e2[10]
  
imports: from __future__ import absolute_import, division, print_function
  import unittest
  import faiss
  import numpy
  from common_faiss_tests import Randu10k, get_dataset_2, Randu10kUnbalanced
label_desc: Use image node_id 9 for calling the IndexAccuracy obj's underlying member method code with example usage: obj.test_IndexPQ_refined() without return types