code: def _read_hkey(buff):
      """Reads from fobj and returns hkey (128 bites integer)."""
      a, b = struct.unpack("=QQ", buff)
      return (a << 64) | b
  
imports: import math
  import os
  import struct
  from typing import Iterator, List, Optional
  import uuid
  from absl import logging
  import six
  from tensorflow_datasets.core import hashing
  from tensorflow_datasets.core.utils import file_utils
  from tensorflow_datasets.core.utils import type_utils
  from tensorflow_datasets.core.utils.lazy_imports_utils import tensorflow
label_desc: Use image node_id 2 for calling a global function with example usage: _read_hkey(buff) and returns: unknown