code: def test_ivf(self):
      self.dump_load_factory("IVF5,Flat")
  
imports: import numpy
  import unittest
  import faiss
  import tempfile
  import os
  import io
  import sys
  import pickle
  from multiprocessing.pool import ThreadPool
label_desc: Use image node_id 4 for calling the TestPickle obj's underlying member method code with example usage: obj.test_ivf() without return types