Code from the readme doesn't work

[fermmm]

In the readme this code is provided:

locales({
  app: app,
  dirs: [__dirname + '/app/locales'],
  defaultLocale: 'zh-CN',
});

And throws this error:
TypeError: Cannot set property '__' of undefined

Only passing app as a parameter works like this:

locales(app, {
  dirs: [__dirname + '/app/locales'],
  defaultLocale: 'zh-CN',
});

So documentation should be fixed