code: def test_nested_parenteses(self):
      index = faiss.index_factory(
          50, "IVF1000(IVF20,SQ4,Refine(SQ8)),Flat"
      )
      q = faiss.downcast_index(index.quantizer)
      qref = faiss.downcast_index(q.refine_index)
      # check we can access the scalar quantizer
      self.assertEqual(qref.sq.code_size, 50)
  
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 14 for calling the TestFactory obj's underlying member method code with example usage: obj.test_nested_parenteses() without return types