How to Hide the "Vulnerability Scanner" Admin Menu

function plt_hide_oopvulns_vulnerability_scanner_menus() {
	//Hide the "Tools → Vulnerability Scanner" menu.
	remove_submenu_page('tools.php', 'oopvulns-vulnerability-scanner');
}

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

Where do I put this code?