Yoast custom sitemap provider

MY_NAMESPACE_sitemap_provider.php

<?php

/**
 * These class and hook allow exposing your data to Yoast, for it to build
 * the sitemap, split it correctly in multiple pages every 1000 entries,
 * and add it to its index. Here's a list of the placeholders I used :
 * - MY_NAMESPACE: your Plugin/theme/custom namespace
 *
 * - MY_CUSTOM_DATATYPE: The type of data you're exposing in those sitemaps
 * - MY_CUSTOM_DATATABLE: Database table hosting your data
 * - MY_MOD_DATE_COLUMN: Last modified date column from the aforementionned table
 * - <YOUR CUSTOM DATA COLUMNS>: Get your data here…
 * - <URL TO THE PAGE>: …and use it to create the pages URIs in your sitemap
 * 
 * You can refer to the Taxonomy sitemap provider
 * included in Yoast to get more details about
 * how Yoast handles these provider classes.
 * @see /wp-content/plugins/wordpress-seo/inc/sitemaps/class-taxonomy-sitemap-provider.php
 *
 * Another approach, without sitemap provider classes:
 * @link https://gist.github.com/leepowers/2b32f734571cbeadc811b93501cfcced
 */

class MY_NAMESPACE_Sitemap_Provider implements WPSEO_Sitemap_Provider
{
    public function handles_type($type)
    {
        if ($type == 'MY_CUSTOM_DATATYPE') {
            return true;
        }

        return false;
    }

    public function get_index_links($max_entries)
    {
        global $wpdb;

        $all_items   = $wpdb->get_results("SELECT MY_MOD_DATE_COLUMN FROM MY_CUSTOM_DATATABLE");
        $index       = [];
        $max_pages   = 1;
        $total_count = count($all_items);
        if ($total_count > $max_entries) {
            $max_pages = (int) ceil($total_count / $max_entries);
        }
        for ($page_counter = 0; $page_counter < $max_pages; $page_counter++) {
            $current_page     = ($page_counter === 0) ? '' : ($page_counter + 1);
            $items             = array_splice($all_items, 0, $max_entries);
            $last_mod         = '2000-01-01 00:00:00';

            if (!$items) {
                continue;
            }
            foreach ($items as $item) {
                $last_mod = max($last_mod, $item->MY_MOD_DATE_COLUMN);
            }
            $index[] = [
                'loc'     => WPSEO_Sitemaps_Router::get_base_url('MY_CUSTOM_DATATYPE-sitemap' . $current_page . '.xml'),
                'lastmod' => $last_mod,
            ];
        }
        return $index;
    }

    public function get_sitemap_links($type, $max_entries, $current_page)
    {
        global $wpdb;
        
        $links  = [];
        $offset = ($current_page > 1) ? (($current_page - 1) * $max_entries) : 0;
        $all_items = $wpdb->get_results(
            "SELECT <YOUR CUSTOM DATA COLUMNS>, MY_MOD_DATE_COLUMN
            FROM MY_CUSTOM_DATATABLE
			LIMIT {$offset}, {$max_entries}"
        );
        foreach ($all_items as $item) {
            $links[] = [
                "loc" => '<URL TO THE PAGE>',
                "mod" => $item->MY_MOD_DATE_COLUMN,
            ];
        }
        return $links;
    }
}

/**
 * Here's the hook to tell Yoast to add your external provider to the list
 * @see /wp-content/plugins/wordpress-seo/inc/sitemaps/class-sitemaps.php:127
 */
function MY_NAMESPACE_sitemap_providers()
{
    return [
        new MY_NAMESPACE_Sitemap_Provider(),
        // ...Put your other sitemap providers here
    ];
}
add_filter('wpseo_sitemaps_providers', 'MY_NAMESPACE_sitemap_providers');

/**
 * Uncomment this line in development environment to disable the sitemap caching.
 */
// add_filter("wpseo_enable_xml_sitemap_transient_caching", "__return_false");

cuz im trying but its not working