code: def _references_content(ref_files):
      """Returns dict<str ref_url, str ref_content>."""
      example_spec = {
          "url": tf.FixedLenFeature([], tf.string),
          "content": tf.FixedLenFeature([], tf.string),
      }
      data = {}
      for ex in generator_utils.tfrecord_iterator(
          ref_files, gzipped=True, example_spec=example_spec
      ):
          data[ex["url"]] = text_encoder.to_unicode(ex["content"])
      return data
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import collections
  import json
  import math
  import os
  import re
  import string
  import tempfile
  import six
  from tensor2tensor.data_generators import generator_utils
  from tensor2tensor.data_generators import problem
  from tensor2tensor.data_generators import text_encoder
  from tensor2tensor.data_generators import tokenizer
  from tensor2tensor.data_generators.wikisum import utils
  from tensor2tensor.layers import modalities
  from tensor2tensor.utils import metrics
  from tensor2tensor.utils import registry
  import tensorflow.compat.v1
label_desc: Use image node_id 6 for calling a global function with example usage: _references_content(ref_files) and returns: data