Set language / locale for Stripe Checkout

my_pmpro_stripe_checkout_session_parameters_locale.php

<?php // copy from below.
/**
 * Set Stripe Checkout language/locale.
 *
 * Possible locale values: https://docs.stripe.com/api/checkout/sessions/create#create_checkout_session-locale
 *
 * 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/
 */
function my_pmpro_stripe_checkout_session_parameters_locale( $checkout_session_params, $morder ) {
	$checkout_session_params['locale'] = 'es-419';

	return $checkout_session_params;
}
add_filter( 'pmpro_stripe_checkout_session_parameters', 'my_pmpro_stripe_checkout_session_parameters_locale', 10, 2 );