code: def generate(cache_fn):
      
      if not os.path.exists(cache_fn):
          print >> sys.stderr, "Can't access `%s`!" % cache_fn
          sys.exit(1)
  
      with SqliteDict(cache_fn) as db:
          for item in _pick_keywords(db):
              yield item
docs: Go thru `cache_fn` and filter keywords. Store them in `keyword_list.json`.
  
      Args:
          cache_fn (str): Path to the file with cache.
  
      Returns:
          list: List of :class:`KeywordInfo` objects.