code: def reverse_vocab(vocab: Vocab) -> InverseVocab:
      """
      Returns value-to-key mapping from key-to-value-mapping.
  
      :param vocab: Key to value mapping.
      :return: A mapping from values to keys.
      """
      return {v: k for k, v in vocab.items()}
  
imports: import argparse
  import json
  import logging
  import os
  from collections import Counter
  from itertools import chain, islice
  from typing import Dict, Iterable, List, Optional, Tuple, Callable
  from sockeye.log import setup_main_logger
  from .None import constants
  from .None import utils
label_desc: Use image node_id 17 for calling a global function with example usage: reverse_vocab(vocab) and returns: unknown