code: def test_ivf_hnsw(self):
      index = faiss.index_factory(123, "IVF100_HNSW,Flat")
      quantizer = faiss.downcast_index(index.quantizer)
      self.assertEqual(quantizer.hnsw.nb_neighbors(1), 32)
  
imports: import numpy
  import unittest
  import gc
  import faiss
  from faiss.contrib import factory_tools
  from faiss.contrib import datasets
label_desc: Use image node_id 8 for calling the TestFactoryV2 obj's underlying member method code with example usage: obj.test_ivf_hnsw() without return types