def test_wsgiRunOnce(self):
        """
        The C{'wsgi.run_once'} key of the C{environ} C{dict} passed to the
        application is set to C{False}.
        """
        once = self.render('GET', '1.1', [], [''])
        once.addCallback(self.environKeyEqual('wsgi.run_once', False))
        return once

        The C{'wsgi.run_once'} key of the C{environ} C{dict} passed to the
        application is set to C{False}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_wsgi.py