Custom button for whatsapp Alert

I have installed Whatsapp module from frappe_whatsapp/frappe_whatsapp at master · shridarpatil/frappe_whatsapp · GitHub and want to have a custom button in sales invoice Send Whatsapp Alert for that I am using this code in scipt.

frappe.ui.form.on('Sales Invoice', {
	refresh(frm) {
		frm.add_custom_button("Send Invoice", function(){
            }, "Send Whatsapp Alert");
// whatsapp function
function whatsapp(send_invoice)
    doc = frappe.get_doc('Sales Invoice', 'name');
        'WhatsApp Notification', 

It is throwing following error.

### App Versions

	"erpnext": "16.0.0-dev",
	"frappe": "16.0.0-dev",
	"frappe_whatsapp": "0.0.2",
	"hrms": "16.0.0-dev",
	"india_compliance": "16.0.0-dev",
	"payments": "0.0.1",
	"webshop": "0.0.1"


Form/Sales Invoice/SL/2023-24/0477


Traceback (most recent call last):
  File "apps/frappe/frappe/", line 110, in application
    response = frappe.api.handle(request)
  File "apps/frappe/frappe/api/", line 49, in handle
    data = endpoint(**arguments)
  File "apps/frappe/frappe/api/", line 36, in handle_rpc_call
    return frappe.handler.handle()
  File "apps/frappe/frappe/", line 49, in handle
    data = execute_cmd(cmd)
  File "apps/frappe/frappe/", line 85, in execute_cmd
    return, **frappe.form_dict)
  File "apps/frappe/frappe/", line 1783, in call
    return fn(*args, **newargs)
  File "apps/frappe/frappe/utils/", line 31, in wrapper
    return func(*args, **kwargs)
TypeError: get_value() missing 1 required positional argument: 'fieldname'

Request Data

	"type": "GET",
	"args": {
		"doctype": "WhatsApp Notification",
		"filters": "{\"event_frequency\":{\"isTrusted\":true}}"
	"headers": {},
	"error_handlers": {},
	"url": "/api/method/frappe.client.get_value",
	"request_id": null

Response Data

	"exception": "TypeError: get_value() missing 1 required positional argument: 'fieldname'",
	"exc_type": "TypeError"

please help me on this.