old_contents: import unittest
  
  from chainer import testing
  from chainer import training
  
  
  class TestExtension(unittest.TestCase):
  
      def test_default_name(self):
          class MyExtension(training.Extension):
              pass
  
          ext = MyExtension()
          self.assertEqual(ext.default_name, 'MyExtension')
  
      def test_deleted_invoke_before_training(self):
          class MyExtension(training.Extension):
              pass
  
          ext = MyExtension()
          with self.assertRaises(AttributeError):
              ext.invoke_before_training
  
      def test_make_extension(self):
          def initialize(trainer):
              pass
  
          @training.make_extension(trigger=(2, 'epoch'), default_name='my_ext',
                                   priority=50, initializer=initialize)
          def my_extension(trainer):
              pass
  
          self.assertEqual(my_extension.trigger, (2, 'epoch'))
          self.assertEqual(my_extension.default_name, 'my_ext')
          self.assertEqual(my_extension.priority, 50)
          self.assertIs(my_extension.initialize, initialize)
  
      def test_make_extension_default_values(self):
          @training.make_extension()
          def my_extension(trainer):
              pass
  
          self.assertEqual(my_extension.trigger, (1, 'iteration'))
          self.assertEqual(my_extension.default_name, 'my_extension')
          self.assertEqual(my_extension.priority, training.PRIORITY_READER)
          self.assertIsNone(my_extension.initialize)
  
      def test_make_extension_deleted_argument(self):
          with self.assertRaises(ValueError):
              @training.make_extension(invoke_before_training=False)
              def my_extension(_):
                  pass
  
      def test_make_extension_unexpected_kwargs(self):
          with self.assertRaises(TypeError):
              @training.make_extension(foo=1)
              def my_extension(_):
                  pass
  
  testing.run_module(__name__, __file__)
  
new_contents: import unittest
  
  from chainer import testing
  from chainer import training
  
  
  class TestExtension(unittest.TestCase):
  
      def test_default_name(self):
          class MyExtension(training.Extension):
              pass
  
          ext = MyExtension()
          self.assertEqual(ext.default_name, 'MyExtension')
  
      def test_deleted_invoke_before_training(self):
          class MyExtension(training.Extension):
              pass
  
          ext = MyExtension()
          with self.assertRaises(AttributeError):
              ext.invoke_before_training
  
      def test_make_extension(self):
          def initialize(trainer):
              pass
  
          @training.make_extension(trigger=(2, 'epoch'), default_name='my_ext',
                                   priority=50, initializer=initialize)
          def my_extension(trainer):
              pass
  
          self.assertEqual(my_extension.trigger, (2, 'epoch'))
          self.assertEqual(my_extension.default_name, 'my_ext')
          self.assertEqual(my_extension.priority, 50)
          self.assertIs(my_extension.initialize, initialize)
  
      def test_make_extension_default_values(self):
          @training.make_extension()
          def my_extension(trainer):
              pass
  
          self.assertEqual(my_extension.trigger, (1, 'iteration'))
          self.assertEqual(my_extension.default_name, 'my_extension')
          self.assertEqual(my_extension.priority, training.PRIORITY_READER)
          self.assertIsNone(my_extension.initialize)
  
      def test_make_extension_deleted_argument(self):
          with self.assertRaises(ValueError):
              @training.make_extension(invoke_before_training=False)
              def my_extension(_):
                  pass
  
      def test_make_extension_unexpected_kwargs(self):
          with self.assertRaises(TypeError):
              @training.make_extension(foo=1)
              def my_extension(_):
                  pass
  
  
  testing.run_module(__name__, __file__)
  
subject: Fix for flake8