class_docstr: Ad-hoc hack to recognize all punctuation and symbols.
class_docstr_tok: ["Ad-hoc","hack","to","recognize","all","punctuation","and","symbols","."]
code: def property_chars(self, prefix):
      return "".join(
          six.unichr(x)
          for x in range(sys.maxunicode)
          if unicodedata.category(six.unichr(x)).startswith(prefix)
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import collections
  import math
  import os
  import re
  import sys
  import time
  import unicodedata
  import numpy
  import six
  from six.moves import range
  from six.moves import zip
  from tensor2tensor.data_generators import text_encoder
  import tensorflow.compat.v1
label_desc: Use image node_id 2 for calling the UnicodeRegex obj's underlying member method code with example usage: obj.property_chars(prefix) and returns: str