react-router npm 中报了如下错误

Question

在参照阮一峰react-router教程学习的时候，按照教程打上去，运行后报如下错误：./src/index.js11:14-25 'react-router' does not contain an export named 'hashHistory'.代码是这样写的：import React from 'react';import ReactDOM from 'react-dom';import './index.css';import App from './App';import { Router, Route, hashHistory } from 'react-router';import registerServiceWorker from './registerServiceWorker';ReactDOM.render((    <Router location={hashHistory}>    <Route path="/" component={App}/>  </Router>    ), document.getElementById('root'));registerServiceWorker();好像是版本的问题，求大神帮忙解决一下！