code: def test_numerical_sort(self):
      dataset = DirectoryParsingLabelDataset(
          self.tmp_dir, numerical_sort=True
      )
  
      assert_is_label_dataset(dataset, self.n_class)
  
      label_names = directory_parsing_label_names(
          self.tmp_dir, numerical_sort=True
      )
      self.assertEqual(
          label_names, ["{}".format(i) for i in range(self.n_class)]
      )
  
imports: import numpy
  import os
  import shutil
  import tempfile
  import unittest
  from chainer import testing
  from chainercv.datasets import directory_parsing_label_names
  from chainercv.datasets import DirectoryParsingLabelDataset
  from chainercv.utils import assert_is_label_dataset
  from chainercv.utils import write_image
label_desc: Use image node_id 3 for calling the TestNumericalSortDirectoryParsingLabelDataset obj's underlying member method code with example usage: obj.test_numerical_sort() without return types