Snippet para solicitar datos de un DTE chileno en el checkout de WooCommerce

woocommerce_snippet_libredte.php

add_filter('woocommerce_checkout_fields', 'custom_override_checkout_fields');
function custom_override_checkout_fields($fields)
{
     $fields['billing']['billing_documento'] = array(
        'type'        => 'select',
        'label'       => __('Documento', 'woocommerce'),
        'options'     => array(33=>'Factura', 39=>'Boleta'),
    	'required'    => true,
    	'class'       => array('form-row-wide'),
    	'clear'       => true,
     );
     $fields['billing']['billing_rut'] = array(
        'label'       => __('RUT', 'woocommerce'),
    	'required'    => true,
    	'class'       => array('form-row-wide'),
    	'clear'       => true,
     );
     $fields['billing']['billing_giro'] = array(
        'label'       => __('Giro', 'woocommerce'),
    	'required'    => false,
    	'class'       => array('form-row-wide'),
    	'clear'       => true,
     );
     return $fields;
}
add_action('woocommerce_admin_order_data_after_shipping_address', 'my_custom_checkout_field_display_admin_order_meta', 10, 1);
function my_custom_checkout_field_display_admin_order_meta($order)
{
    $documentos = [33=>'Factura', 39=>'Boleta'];
    echo '<h3>Datos DTE</h3>';
    echo '<p><strong>'.__('Documento').':</strong><br/>'.$documentos[get_post_meta($order->get_id(), '_billing_documento', true)].'</p>';
    echo '<p><strong>'.__('RUT').':</strong><br/>'.get_post_meta($order->get_id(), '_billing_rut', true).'</p>';
    echo '<p><strong>'.__('Giro').':</strong><br/>'.get_post_meta($order->get_id(), '_billing_giro', true).'</p>';
}