Change Projects Custom Post Type name in Divi, still works with Portfolio

gistfile1.txt

$singular_name = 'Book'; // Enter the singular name for your new post type within the quotes
$plural_name = 'Books'; // Enter the plural name of your new post type within the quotes

function divi_projects_rename() {

    global $wp_post_types;
    global $singular_name;
    global $plural_name;

    $labels = $wp_post_types['project']->labels;

    $labels->menu_name = __( $plural_name, 'Divi' );
    $labels->name = __( $plural_name, 'Divi' );
	$labels->singular_name = __( $singular_name, 'Divi' );
	$labels->add_new = __( 'Add New', 'Divi' );
	$labels->add_new_item = __( 'Add New '.$singular_name, 'Divi' );
	$labels->edit_item = __( 'Edit '.$singular_name, 'Divi' );
	$labels->new_item = __( 'New '.$singular_name, 'Divi' );
	$labels->all_items = __( 'All '.$plural_name, 'Divi' );
	$labels->view_item = __( 'View '.$plural_name, 'Divi' );
	$labels->search_items = __( 'Search '.$plural_name, 'Divi' );
} 

function divi_projects_slug_rename() {

	global $plural_name;
	$slug_name = strtolower($plural_name);

	return array(
		'feeds' => true,
		'slug' => $slug_name,
		'with_front' => false,
	);
}
add_filter( 'et_project_posttype_rewrite_args', 'divi_projects_slug_rename' );

Question: where do you call divi_projects_rename()?