class_docstr: Dictionary wrapper that prevents modifications to the dictionary 
class_docstr_tok: ["Dictionary","wrapper","that","prevents","modifications","to","the","dictionary"]
code: def _set_callback(self, key_value, *_):
      if self._update_func is not None:
          if callable(self._update_func):
              res = self._update_func(self._update_obj, key_value)
          else:
              res = self._update_func
  
          if not res:
              return None
          return res
      return key_value
  
imports: import itertools
  import json
  from copy import copy
  from logging import getLogger
  import six
  import yaml
label_desc: Use image node_id 4 for calling the ProxyDictPreWrite obj's underlying member method code with example usage: obj._set_callback(key_value) and returns: key_value, res, None