I am extending ClientListScreenWidget in odoo 9  but I unable to do that any help will be appreciated, given below is my code.

odoo.define('pos_point_redemption.widgets', function (require) {
"use strict";
console.log("pos_point_redemption widgets")
module = instance.point_of_sale;
var PosBaseWidget = require('point_of_sale.BaseWidget');
var chrome = require('point_of_sale.chrome');
var gui = require('point_of_sale.gui');
var models = require('point_of_sale.models');
var screens = require('point_of_sale.screens');
var core = require('web.core');
var Model = require('web.DataModel');
var formats = require('web.formats');
screens.ClientListScreenWidget.extend({
 init: function(parent, options){
 this._super(parent, options);
 this.partner_cache = new DomCache();
 },
});
});