def test_pluginsType(self):
        """
        L{TwistOptions.plugins} is a mapping of available plug-ins.
        """
        options = TwistOptions()
        plugins = options.plugins

        for name in plugins:
            self.assertIsInstance(name, str)
            self.assertIsInstance(plugins[name], ServiceMaker)

        L{TwistOptions.plugins} is a mapping of available plug-ins.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/application/twist/test/test_options.py