How to use the muffin.utils.LStruct function in muffin

def test_struct():
    from muffin.utils import Struct, LStruct

    data = Struct({'test': 42})
    assert data.test == 42

    data.test = 21
    assert data.test == 21

    settings = LStruct({'option': 'value'})
    assert settings.option == 'value'

    settings.option2 = 'value2'
    settings.lock()
    settings.lock()

    with pytest.raises(RuntimeError):
        settings.test = 42

logging.config.dictConfig(LOGGING_CFG)

        # Setup CLI
        self.manage = Manager(self)

        self._error_handlers = {}

        # Setup static files
        if isinstance(self.cfg.STATIC_FOLDERS, str):
            self.cfg.STATIC_FOLDERS = [self.cfg.STATIC_FOLDERS]

        elif not isinstance(self.cfg.STATIC_FOLDERS, list):
            self.cfg.STATIC_FOLDERS = list(self.cfg.STATIC_FOLDERS)

        # Setup plugins
        self.plugins = self.ps = LStruct()
        for plugin in self.cfg.PLUGINS:
            try:
                self.install(plugin)
            except Exception as exc:  # noqa
                self.logger.error('Plugin is invalid: %s', plugin)
                self.logger.exception(exc)

def __init__(self, app=None, **options):
        """Save application and create he plugin's configuration."""
        self.config = self.cfg = LStruct(options)
        self.app = app
        if app is not None:
            app.install(self)

def cfg(self):
        """Load the application configuration.

        This method loads configuration from python module.
        """
        config = LStruct(self.defaults)
        module = config['CONFIG'] = os.environ.get(
            CONFIGURATION_ENVIRON_VARIABLE, config['CONFIG'])

        if module:
            try:
                module = import_module(module)
                config.update({
                    name: getattr(module, name) for name in dir(module)
                    if name == name.upper() and not name.startswith('_')
                })

            except ImportError as exc:
                config.CONFIG = None
                self.logger.error("Error importing %s: %s", module, exc)

        # Patch configuration from ENV