How to Hide the "TM-Cypress Options Editor" Admin Menu

function plt_hide_treemagic_cypress_menus() {
	//Hide the "Settings → TM-Cypress Options Editor" menu.
	remove_submenu_page('options-general.php', 'TM-Cypress.php');
}

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

Where do I put this code?