code: def _setup_depth_one_dummy_data(
      tmp_dir, n_class, n_img_per_class, size, color, suffix
  ):
      for i in range(n_class):
          class_dir = os.path.join(tmp_dir, "class_{}".format(i))
          os.makedirs(class_dir)
          for j in range(n_img_per_class):
              path = os.path.join(
                  class_dir, "img{}.{}".format(j, suffix)
              )
              _save_img_file(path, size, color)
          open(os.path.join(class_dir, "dummy_file.XXX"), "a").close()
  
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 2 for calling a global function with example usage: _setup_depth_one_dummy_data(tmp_dir, n_class, n_img_per_class, size, color, suffix) without return types