How to use the evergreen-ui.extractStyles function in evergreen-ui

static getInitialProps({ renderPage }) {
    const page = renderPage()
    // `css` is a string with css from both glamor and ui-box.
    // No need to get the glamor css manually if you are using it elsewhere in your app.
    //
    // `hydrationScript` is a script you should render on the server.
    // It contains a stringified version of the glamor and ui-box caches.
    // Evergreen will look for that script on the client and automatically hydrate
    // both glamor and ui-box.
    const { css, hydrationScript } = extractStyles()

    return {
      ...page,
      css,
      hydrationScript
    }
  }

static getInitialProps({ renderPage }) {
    const page = renderPage();
    const { css, hydrationScript } = extractStyles();

    return {
      ...page,
      css,
      hydrationScript
    };
  }