How to Hide the "Access package" Admin Menu

function plt_hide_triggerfish_bytbil_accesspaket_menus() {
	//Hide the "Settings → Access package" menu.
	remove_submenu_page('options-general.php', 'access-package.php');
}

add_action('admin_menu', 'plt_hide_triggerfish_bytbil_accesspaket_menus', 11);

Where do I put this code?