code: def get_pairs(word):
      """
      Return set of symbol pairs in a word.
  
      Word is represented as tuple of symbols (symbols being variable-length strings).
      """
      pairs = set()
      prev_char = word[0]
      for char in word[1:]:
          pairs.add((prev_char, char))
          prev_char = char
      return pairs
  
imports: import json
  import os
  from functools import lru_cache
  from typing import TYPE_CHECKING, List, Optional, Tuple
  import regex
  from ...tokenization_utils import AddedToken, PreTrainedTokenizer
  from ...utils import logging
label_desc: Use image node_id 2 for calling a global function with example usage: get_pairs(word) and returns: pairs