code: def test_add_called_before_training_extension(self):
      class MyDummyCallableClass(DummyCallableClass):
          def __init__(self, test_case):
              super(MyDummyCallableClass, self).__init__(test_case)
              self.is_called_before_training = False
  
          def __call__(self, trainer):
              if trainer.is_before_training:
                  self.is_called_before_training = True
              return super(MyDummyCallableClass, self).__call__(trainer)
  
      dummy_callable_class = MyDummyCallableClass(self)
      self.trainer.extend(
          dummy_callable_class, call_before_training=True
      )
      self.trainer.run()
      self.assertTrue(dummy_callable_class.is_called)
      self.assertTrue(dummy_callable_class.is_called_before_training)
      self.assertTrue(dummy_callable_class.is_finalized)
  
imports: import time
  import traceback
  import unittest
  from chainer import testing
  from chainer import training
label_desc: Use image node_id 7 for calling the TestTrainer obj's underlying member method code with example usage: obj.test_add_called_before_training_extension() and returns: super