code: def test_file_reader():
      for use_root in [False, True]:
          for use_labels in [False, True]:
              for shuffle in [False, True]:
                  yield _test_reader_files_arg, use_root, use_labels, shuffle
  
imports: import glob
  import numpy
  import nvidia.dali.fn
  import os
  import random
  import tempfile
  from nvidia.dali import Pipeline, pipeline_def
  from nose_utils import assert_raises
  from test_utils import compare_pipelines
label_desc: Use image node_id 6 for calling a global function with example usage: test_file_reader() without return types