code: def on_error(self, trainer, exception, tb):
      traceback.print_tb(tb)
      self.is_error_handled = True
  
imports: import time
  import traceback
  import unittest
  from chainer import testing
  from chainer import training
label_desc: Use image node_id 3 for calling the ErrorHandlingExtension obj's underlying member method code with example usage: obj.on_error(trainer, exception, tb) without return types