code: def test_hnsw_exact_distances(self):
      d = self.xq.shape[1] * 8
      nq = self.xq.shape[0]
  
      index = faiss.IndexBinaryHNSW(d, 16)
      index.add(self.xb)
      Dists, Ids = index.search(self.xq, 3)
  
      for i in range(nq):
          for j, dj in zip(Ids[i], Dists[i]):
              ref_dis = binary_dis(self.xq[i], self.xb[j])
              self.assertEqual(dj, ref_dis)
  
imports: import os
  import numpy
  import unittest
  import faiss
  from common_faiss_tests import compare_binary_result_lists, make_binary_dataset
label_desc: Use image node_id 2 for calling the TestHNSW obj's underlying member method code with example usage: obj.test_hnsw_exact_distances() without return types