Make bstate field optional for Paid Memberships Pro checkout

pmpro-bstate-optional.php

<?php
/**
 * Remove the bstate requirement from billing fields generated by PMPro or Address for Free Levels Add On
 * Add this code to your site by following this guide - https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */
function my_pmpro_remove_bstate_required( $pmpro_required_billing_fields ){

    //remove field ID's from array to make fields required
    $remove_field = array('bstate');

    //loop through the $remove_field array and unset each billing field to make it optional.
    foreach($remove_field as $field){
        unset($pmpro_required_billing_fields[$field]);
    }            

    return $pmpro_required_billing_fields;
}

add_filter('pmpro_required_billing_fields', 'my_pmpro_remove_bstate_required', 50 );