code: def post_hook(self):
      def callback(key):
          if key not in self.key_to_times:
              raise ValueError()
  
          self.ext_module.synchronize(device_id=self.device_id)
          self.key_to_times[key][1] = self.timer()
  
      return callback
  
imports: from __future__ import absolute_import
  import csv
  import os
  import time
  from collections import OrderedDict
  from contextlib import contextmanager
  from importlib import import_module
  import numpy
  from nnabla.ext_utils import import_extension_module
  from .base import FunctionHookCallbackBase
label_desc: Use image node_id 3 for calling the CpuTimerCallback obj's underlying member method code with example usage: obj.post_hook() and returns: callback