code: def test_IDMap(self):
      sub_index = faiss.IndexFlatL2(d)
      index = faiss.IndexIDMap(sub_index)
      index.add_with_ids(xb, np.arange(len(xb), dtype="int64"))
      del sub_index
      gc.collect()
      index.add_with_ids(xb, np.arange(len(xb), dtype="int64"))
  
file_path: faiss/tests/test_referenced_objects.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import numpy
  import unittest
  import faiss
  import sys
  import gc
label_desc: Use image node_id 6 for calling the TestReferenced obj's underlying member method code with example usage: obj.test_IDMap() without return types