react-route动态路由，它的子路由路径配置在什么地方？ 配置报错 

一般的路由配置，路径path和组件component总是一一对应的，如：

const routes = {
  path: '/',
  component: App,
  indexRoute: { component: Dashboard },
  childRoutes: [
    { path: 'about', component: About },
    {
      path: 'inbox',
      component: Inbox,
      childRoutes: [{
        path: 'messages/:id',
        onEnter: ({ params }, replace) => replace(`/messages/${params.id}`)
      }]
    },
    {
      component: Inbox,
      childRoutes: [{
        path: 'messages/:id', component: Message
      }]
    }
  ]
}

但动态路由的配置就看不懂了，子路由路径到底配置在哪儿？

const CourseRoute = {
  path: 'course/:courseId',

  getChildRoutes(partialNextState, callback) {
    require.ensure([], function (require) {
      callback(null, [
        require('./routes/Announcements'),
        require('./routes/Assignments'),
        require('./routes/Grades'),
      ])
    })
  },

  getIndexRoute(partialNextState, callback) {
    require.ensure([], function (require) {
      callback(null, {
        component: require('./components/Index'),
      })
    })
  },

  getComponents(nextState, callback) {
    require.ensure([], function (require) {
      callback(null, require('./components/Course'))
    })
  }
}