I want to show alert box on button click but getting error iam sharing all files and error.

Wizard.js

odoo.define('wizard.wizard', function (require) {

"use strict";

var ajax = require('web.ajax');

var core = require('web.core');

var Dialog = require("web.Dialog");

var Widget = require("web.Widget");

var rpc = require("web.rpc");

var _t = core._t;

var PaymentForm = Widget.extend({

initialize: function () {

alert('End');

},

events: {

'click #o_payment_form_add_pm': 'addPmEvent'

},

addPmEvent: function (ev) {

ev.stopPropagation();

ev.preventDefault();

alert('click');

},

});

alert('start');

});

Wizard.xml

<template id="assets_frontend" inherit_id="web.assets_backend" name="wizard2">

<xpath expr="." position="inside">

<script type="text/javascript" src="/wizard/static/src/js/wizard.js"></script>

</xpath>

</template>

<record model="ir.ui.view" id="wizard_form_view">

<field name="name">wizard.form</field>

<field name="model">wizard</field>

<field name="arch" type="xml">

<form string="wizard">

<header>

<button name="reload_on_button" string="call web service" class="your_class"/> <!--type="object"-->

<button id="o_payment_form_add_pm" string="js" class="btn btn-primary btn-lg mb8 mt8"/>

</header>

<sheet>

<group>

<group string="">

<field name="wizardname" > </field>

<field name="current_date" > </field>

</group>

</group>

</sheet>

</form>

</field>

</record>

ERROR

Uncaught TypeError: Cannot read property 'then' of undefined

http://localhost:8069/web/content/434-7301179/web.assets_backend.js:471

Traceback:

TypeError: Cannot read property 'then' of undefined

at Class.execute_action (http://localhost:8069/web/content/434-7301179/web.assets_backend.js:471:684)

at Class.<anonymous> (http://localhost:8069/web/content/365-3f13533/web.assets_common.js:3908:11)

at Class.trigger (http://localhost:8069/web/content/365-3f13533/web.assets_common.js:3906:180)

at Class._trigger_up (http://localhost:8069/web/content/365-3f13533/web.assets_common.js:3912:365)

at Class._trigger_up (http://localhost:8069/web/content/365-3f13533/web.assets_common.js:3912:449)

at Class.trigger_up (http://localhost:8069/web/content/365-3f13533/web.assets_common.js:3912:280)

at Class._callButtonAction (http://localhost:8069/web/content/434-7301179/web.assets_backend.js:1263:1694)

at Object.<anonymous> (http://localhost:8069/web/content/434-7301179/web.assets_backend.js:1363:992)

at Object.<anonymous> (http://localhost:8069/web/content/365-3f13533/web.assets_common.js:802:681)

at fire (http://localhost:8069/web/content/365-3f13533/web.assets_common.js:796:299)