Exibir o filtro por taxonomy na listagem de posts de CPT

gistfile1.txt

    add_action( 'restrict_manage_posts', 'my_restrict_manage_posts' );
    function my_restrict_manage_posts() {
    $CPT = "SEU_CPT";
    $slug_taxonamy = "SLUG_DA_TAXONOMY";
        global $typenow;
        if ($typenow == $CPT) {

            $filters = array($slug_taxonamy);

            foreach ($filters as $tax_slug) {
                // retrieve the taxonomy object
                $tax_obj = get_taxonomy($tax_slug);
                $tax_name = $tax_obj->labels->name;

               
                echo "<select name='$tax_slug' id='$tax_slug' class='postform'>";
                echo "<option value=''>Show All $tax_name</option>";
                generate_taxonomy_options($tax_slug,0,0);
                echo "</select>";
            }
        }
    }
    function generate_taxonomy_options($tax_slug, $parent = '', $level = 0) {
        $args = array('show_empty' => 1);
        if(!is_null($parent)) {
            $args = array('parent' => $parent);
        } 
        $terms = get_terms($tax_slug,$args);
        $tab='';
        for($i=0;$i<$level;$i++){
            $tab.='--';
        }
        foreach ($terms as $term) {
            echo '<option value='. $term->slug, $_GET[$tax_slug] == $term->slug ? ' selected="selected"' : '','>' .$tab. $term->name .' (' . $term->count .')</option>';
            generate_taxonomy_options($tax_slug, $term->term_id, $level+1);
        }
    }