code: def _replace_none(dictionary):
      for key in list(dictionary.keys()):
          if dictionary[key] == "None":
              dictionary[key] = None
          elif isinstance(dictionary[key], dict):
              dictionary[key] = _replace_none(dictionary[key])
      return dictionary
  
imports: from __future__ import with_statement
  from __future__ import absolute_import
  from collections import MutableMapping, OrderedDict
  import copy
  import json
  import logging
  import os
  from io import open
  from allennlp.common.checks import ConfigurationError
  from allennlp.common.file_utils import cached_path
label_desc: Use image node_id 5 for calling a global function with example usage: _replace_none(dictionary) and returns: dictionary