def setUp(self):
        """
        Create a logger for test L{LoggingFile} instances to use.
        """
        self.publisher = LogPublisher()
        self.logger = Logger(observer=self.publisher)

        Create a logger for test L{LoggingFile} instances to use.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/logger/test/test_io.py