code: def test_cluster1d(self):
      self.subtest_cluster1d(20, 20)
      self.subtest_cluster1d(1000, 20)
      self.subtest_cluster1d(1000, 256)
  
imports: from __future__ import absolute_import, division, print_function
  import numpy
  import faiss
  import unittest
  import array
  from common_faiss_tests import get_dataset_2
label_desc: Use image node_id 3 for calling the TestClustering1D obj's underlying member method code with example usage: obj.test_cluster1d() without return types