How to Hide the "IP Threat Blocker" Admin Menu

function plt_hide_ip_threat_blocker_by_musubu_menus() {
	//Hide the "Settings → IP Threat Blocker" menu.
	remove_submenu_page('options-general.php', 'iptbbm-options');
}

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

Where do I put this code?