code: def _map_tokens_batch(tokens, char_map):
      """Performs token mapping, in batch mode
  
      Arguments
      ---------
      tokens: iterable
          a list of token sequences
      char_map: dict
          a token-to-character mapping
  
      Returns
      -------
      result: list
          a list of lists of characters
      """
      return [[char_map[char] for char in item] for item in tokens]
  
imports: from functools import reduce
  from speechbrain.wordemb.util import expand_to_chars
  import speechbrain
  import torch
  import re
label_desc: Use image node_id 17 for calling a global function with example usage: _map_tokens_batch(tokens, char_map) and returns: unknown