Add user_id as a data variable for email templates in PMPro

my_pmpro_email_custom_data.php

<?php
/* This code will add user_id as a data variable for email templates in PMPro.
 *
 * You can add this recipe to your site by creating a custom plugin
 * or using the Code Snippets plugin available for free in the WordPress repository.
 * Read this companion article for step-by-step directions on either method.
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */

// begin copying code below here
function my_pmpro_email_custom_data($data, $email) {
	if( ! empty( $data['user_login'] ) ) {
		$user = get_user_by( "login", $data['user_login'] );		
		$data['user_id'] = $user->ID;
	}

	return $data;
}
add_filter( "pmpro_email_data", "my_pmpro_email_custom_data", 10, 2 );