def testLoadApplication(self):
        """
        Test loading an application file in different dump format.
        """
        a = service.Application("hello")
        baseconfig = {'file': None, 'source': None, 'python':None}
        for style in 'source pickle'.split():
            config = baseconfig.copy()
            config[{'pickle': 'file'}.get(style, style)] = 'helloapplication'
            sob.IPersistable(a).setStyle(style)
            sob.IPersistable(a).save(filename='helloapplication')
            a1 = app.getApplication(config, None)
            self.assertEqual(service.IService(a1).name, "hello")
        config = baseconfig.copy()
        config['python'] = 'helloapplication'
        with open("helloapplication", 'w') as f:
            f.writelines([
                "from twisted.application import service\n",
                "application = service.Application('hello')\n",
            ])
        a1 = app.getApplication(config, None)
        self.assertEqual(service.IService(a1).name, "hello")

        Test loading an application file in different dump format.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_application.py