code: def testFileIteratorRecursive(self):
      target_files = [
          ("0.ext", b"hello world"),
          ("a/1.ext", b"123456"),
          ("a/2.ext", b"abcd"),
          ("b/c/3.ext", b"9999"),
          ("b/z/3.ext", b"qwerty"),
          ("d/4.ext", b"mary had a little lamb"),
          ("d/e/5.ext", b"zzzzzzzz"),
          ("d/e/f/g/6.ext", b"yyyyyyyyyyy"),
      ]
      extra_files = [
          ("stuff.txt", b"some stuff"),
          ("a/q/r/file", b"more stuff"),
      ]
  
      root_dir = self.create_tempdir().full_path
      for path, contents in target_files + extra_files:
          abs_path = os.path.join(root_dir, path)
          tf.gfile.MakeDirs(os.path.dirname(abs_path))
          tf.gfile.GFile(abs_path, mode="w").write(contents)
  
      file_iterator = pipeline.file_iterator(
          root_dir, "ext", recurse=True
      )
  
      self.assertEqual(
          set(contents for _, contents in target_files),
          set(file_iterator),
      )
  
imports: import os
  from absl.testing import absltest
  from magenta.common import testing_lib
  from magenta.pipelines import pipeline
  from magenta.pipelines import statistics
  import tensorflow.compat.v1
label_desc: Use image node_id 1 for calling the PipelineTest obj's underlying member method code with example usage: obj.testFileIteratorRecursive() without return types