extjs报错variety.js:2 Uncaught TypeError: Ext.define is not a function at variety.js:2

Question

Ext.define('exploit.hello.variety',{

extend: 'Ext.panel.Panel',

title: "west",

    layout: "accordion",  //设置为手风琴布局

    layoutConfig: {

        animate: true

    },

    width: 250,

    minWidth: 90,

    region: "west", //设置方位

    split: true,

    collapsible: true,

    items: [

                { title: "嵌套面板一", html: "嵌套面板一", iconCls: "save" },

                { title: "嵌套面板二", html: "嵌套面板二", iconCls: "search" },

                { title: "嵌套面板三", html: "嵌套面板三", iconCls: "back" },

                { title: "嵌套面板四", html: "嵌套面板四", iconCls: "12" }

           ]

});