code: def record_set(session_factory, bucket, key_prefix, start_date, specify_hour=False):
      
  
      s3 = local_session(session_factory).client('s3')
  
      records = []
      key_count = 0
  
      date = start_date.strftime('%Y/%m/%d')
      if specify_hour:
          date += "/{}".format(start_date.hour)
      else:
          date += "/00"
  
      marker = "{}/{}/resources.json.gz".format(key_prefix.strip("/"), date)
  
      p = s3.get_paginator('list_objects_v2').paginate(
          Bucket=bucket,
          Prefix=key_prefix.strip('/') + '/',
          StartAfter=marker,
      )
  
      with ThreadPoolExecutor(max_workers=20) as w:
          for key_set in p:
              if 'Contents' not in key_set:
                  continue
              keys = [k for k in key_set['Contents']
                      if k['Key'].endswith('resources.json.gz')]
              key_count += len(keys)
              futures = map(lambda k: w.submit(
                  get_records, bucket, k, session_factory), keys)
  
              for f in as_completed(futures):
                  records.extend(f.result())
  
      log.info("Fetched %d records across %d files" % (
          len(records), key_count))
      return records
docs: Retrieve all s3 records for the given policy output url
  
      From the given start date.