code: def test_codec(self):
      for i in range(16):
          print("Testing nbits=%d" % (i + 1))
          self.do_test_codec(i + 1)
  
imports: from __future__ import absolute_import, division, print_function
  import numpy
  import faiss
  import unittest
label_desc: Use image node_id 3 for calling the TestProductQuantizer obj's underlying member method code with example usage: obj.test_codec() without return types