How to use the react-native-modal.Mixin function in react-native-modal

Image,
  Navigator,
} = React;

var UserActions = require('../Actions/UserActions');
var UserStore = require('../Stores/UserStore');
var Video = require('react-native-video');
var Modal = require('react-native-modal');
var LinearGradient = require('react-native-linear-gradient');
var UserActions = require('../Actions/UserActions');
var styles = require('./Styles');
var UserStoreSync = require('../Mixins/UserStoreSync');
var DeviceHeight = require('Dimensions').get('window').height;

var LoginScreen = React.createClass({
  mixins: [UserStoreSync, Modal.Mixin],

  login() {
    UserActions.newFacebookSession();
  },

  afterUpdateUserFromStore() {
    var user = UserStore.getState();

    if (user.get('email')) {
      this.props.navigator.replace({id: 'user-info'});
    }
  },

  showModalTransition(transition) {
    transition('opacity', {duration: 200, begin: 0, end: 1});
    transition('height', {duration: 200, begin: DeviceHeight * 2, end: DeviceHeight});