code: def test_add_function_extension(self):
      self.is_called = False
  
      def dummy_function(trainer):
          self.is_called = True
  
      self.trainer.extend(dummy_function)
      self.trainer.run()
      self.assertTrue(self.is_called)
  
imports: import time
  import traceback
  import unittest
  from chainer import testing
  from chainer import training
label_desc: Use image node_id 11 for calling the TestTrainer obj's underlying member method code with example usage: obj.test_add_function_extension() without return types