code: def extract_labels(self, setn):
      if not os.path.exists(self.devkit):
          raise IOError(
              (
                  "Metadata file {} not found. Ensure you have ImageNet downloaded"
              ).format(self.devkit)
          )
  
      with tarfile.open(self.devkit, "r:gz") as tf:
          synsetfile = "ILSVRC2012_devkit_t12/data/meta.mat"
          valfile = "ILSVRC2012_devkit_t12/data/ILSVRC2012_validation_ground_truth.txt"
  
          if setn == "train":
              # get the synset mapping by hacking around matlab's terrible compressed format
              meta_buff = tf.extractfile(synsetfile).read()
              decomp = zlib.decompressobj()
              self.synsets = re.findall(
                  re.compile("n\d+"), decomp.decompress(meta_buff[136:])
              )
              return {s: i for i, s in enumerate(self.synsets)}
          elif setn == "val":
              # get the ground truth validation labels and offset to zero
              return {
                  "%08d" % (i + 1): int(x) - 1
                  for i, x in enumerate(tf.extractfile(valfile))
              }
          else:
              raise ValueError("Unknown set name: {}".format(setn))
  
imports: from builtins import str, zip
  from configargparse import ArgParser
  from itertools import repeat
  from neon import logger
  from neon.util.persist import ensure_dirs_exist
  from PIL import Image
  import logging
  import multiprocessing
  import numpy
  import os
  import re
  import shutil
  import tarfile
  import tqdm
  import zlib
label_desc: Use image node_id 3 for calling the IngestI1K obj's underlying member method code with example usage: obj.extract_labels(setn) and returns: unknown, unknown