code: def tfrecord_fname(out_dir, shard_id, idx=None):
      fname = os.path.join(out_dir, REF_SHARD_FILE % shard_id)
      if idx is not None:
          fname += ".%d" % idx
      return fname
  
imports: import datetime
  import json
  import math
  import multiprocessing
  import os
  import random
  import asyncio
  import aiohttp
  import tensorflow
  from tensor2tensor.data_generators.wikisum import html
  from tensor2tensor.data_generators.wikisum import utils
label_desc: Use image node_id 6 for calling a global function with example usage: tfrecord_fname(out_dir, shard_id, idx) and returns: fname