class_docstr: Pre-trained XLNet Tokenizer.
  
  Args:
      pretrained_model_name (optional): a `str`, the name of
          pre-trained model (e.g., `xlnet-base-uncased`). Please refer to
          :class:`~texar.torch.modules.PretrainedXLNetMixin` for
          all supported models.
          If None, the model name in :attr:`hparams` is used.
      cache_dir (optional): the path to a folder in which the
          pre-trained models will be cached. If `None` (default),
          a default directory (``texar_data`` folder under user's home
          directory) will be used.
      hparams (dict or HParams, optional): Hyperparameters. Missing
          hyperparameter will be set to default values. See
          :meth:`default_hparams` for the hyperparameter structure
          and default values.
class_docstr_tok: ["Pre-trained","XLNet","Tokenizer",".","Args",":","pretrained_model_name","(","optional",")",":","a","`","str","`",",","the","name","of","pre-trained","model","(","e.g.",",","`","xlnet-base-uncased","`",")",".","Please","refer","to",":","class",":","`","~texar.torch.modules.PretrainedXLNetMixin","`","for","all","supported","models",".","If","None",",","the","model","name","in",":","attr",":","`","hparams","`","is","used",".","cache_dir","(","optional",")",":","the","path","to","a","folder","in","which","the","pre-trained","models","will","be","cached",".","If","`","None","`","(","default",")",",","a","default","directory","(","``","texar_data","``","folder","under","user","'s","home","directory",")","will","be","used",".","hparams","(","dict","or","HParams",",","optional",")",":","Hyperparameters",".","Missing","hyperparameter","will","be","set","to","default","values",".","See",":","meth",":","`","default_hparams","`","for","the","hyperparameter","structure","and","default","values","."]
docstr: Maps a sequence of tokens (string) in a single string.
docstr_tok: ["Maps","a","sequence","of","tokens","(","string",")","in","a","single","string","."]
code: def map_token_to_text(self, tokens: List[str]) -> str:
      r"""Maps a sequence of tokens (string) in a single string."""
      out_string = (
          "".join(tokens).replace(SPIECE_UNDERLINE, " ").strip()
      )
      return out_string
  
imports: from typing import Any, Dict, List, Optional, Tuple
  import os
  import unicodedata
  from shutil import copyfile
  import sentencepiece
  from texar.tf.modules.pretrained.xlnet import PretrainedXLNetMixin
  from texar.tf.data.tokenizers.tokenizer_base import TokenizerBase
  from texar.tf.utils.utils import truncate_seq_pair
label_desc: Use image node_id 10 for calling the XLNetTokenizer obj's underlying member method code with example usage: obj.map_token_to_text(tokens) and returns: out_string