def setUp(self):
        """
        Create a L{WSGIResource} with synchronous threading objects and a no-op
        application object.  This is useful for testing certain things about
        the resource implementation which are unrelated to WSGI.
        """
        self.resource = WSGIResource(
            SynchronousReactorThreads(), SynchronousThreadPool(),
            lambda environ, startResponse: None)

        Create a L{WSGIResource} with synchronous threading objects and a no-op
        application object.  This is useful for testing certain things about
        the resource implementation which are unrelated to WSGI.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_wsgi.py