class_docstr: Splits a string into tokens, and joins them back.
class_docstr_tok: ["Splits","a","string","into","tokens",",","and","joins","them","back","."]
docstr: Joins tokens into a string.
code: def join(self, tokens):
      """Joins tokens into a string."""
      if self._alphanum_only:
          return " ".join(tokens)
      else:
          # Fully invertible
          return "".join(tokens)
  
imports: from __future__ import unicode_literals
  import abc
  import hashlib
  import json
  import re
  from tensorflow_datasets.core.utils.lazy_imports_utils import tensorflow
label_desc: Use image node_id 5 for calling the Tokenizer obj's underlying member method code with example usage: obj.join(tokens) and returns: str, str