text: import {createAppContainer, createSwitchNavigator} from 'react-navigation';
  import Login from './pages/Login';
  import List from './pages/List';
  import Book from './pages/Book';
  
  
  const Routes = createAppContainer(
      createSwitchNavigator({
          Login,
          List,
          Book
      })
  );
  
  export default Routes;