code: def _unquote_or_none(s):
      """None-safe wrapper around url_unescape to handle unmatched optional
      groups correctly.
  
      Note that args are passed as bytes so the handler can decide what
      encoding to use.
      """
      if s is None:
          return s
      return url_unescape(s, encoding=None, plus=False)
  
imports: from __future__ import absolute_import, division, print_function
  import re
  from functools import partial
  from tornado import httputil
  from tornado.httpserver import _CallableAdapter
  from tornado.escape import url_escape, url_unescape, utf8
  from tornado.log import app_log
  from tornado.util import basestring_type, import_object, re_unescape, unicode_type
label_desc: Use image node_id 1 for calling a global function with example usage: _unquote_or_none(s) and returns: url_unescape, s