code: def test_PQ(self):
      self.do_test("IVF64,PQ4np")
  
imports: import faiss
  import unittest
  import numpy
  import platform
  import os
  import random
  import tempfile
  from faiss.contrib import datasets
  from faiss.contrib import inspect_tools
  from faiss.contrib import evaluation
  from faiss.contrib import ivf_tools
  from faiss.contrib import clustering
  from faiss.contrib import big_batch_search
  from common_faiss_tests import get_dataset_2
label_desc: Use image node_id 4 for calling the TestBigBatchSearch obj's underlying member method code with example usage: obj.test_PQ() without return types