How to use the native-base.OSTheme.setOSTheme function in native-base

/**
 * react-native-web + native-base-web starter app
 * Chion82 https://github.com/Chion82/rnweb-native-base-starter
 * https://miria.moe
 */

import { AppRegistry } from 'react-native';
import Entry from './app/entry/index';
import { OSTheme } from 'native-base';

//Use IOS theme for our web app
OSTheme.setOSTheme('ios');

AppRegistry.registerComponent('App', () => Entry);
AppRegistry.runApplication('App', {
  rootTag: document.getElementById('react-root')
});