code: def write_ref_content(url, ref, f):
      if not ref:
          return False
      ex = make_example_from_ref(url, ref)
      if ex is None:
          return False
      f.write(ex.SerializeToString())
      return True
  
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 8 for calling a global function with example usage: write_ref_content(url, ref, f) and returns: True, False, False