docstr: when nsplits = 1, PLSQ should be almost the same as LSQ
code: def test_accuracy2(self):
      """when nsplits = 1, PLSQ should be almost the same as LSQ"""
      recall1 = self.eval_index_accuracy("PLSQ1x3x5_Nqint8")
      recall2 = self.eval_index_accuracy("LSQ3x5_Nqint8")
      diff = abs(recall1 - recall2)  # 273 vs 275 in OSX
      self.assertGreaterEqual(5, diff)
  
imports: import numpy
  import faiss
  import unittest
  from faiss.contrib import datasets
label_desc: Use image node_id 2 for calling the TestIndexProductLocalSearchQuantizer obj's underlying member method code with example usage: obj.test_accuracy2() without return types