How to Hide the "Global Weather Pro" Admin Menu

function plt_hide_global_weather_pro_menus() {
	//Hide the "Settings → Global Weather Pro" menu.
	remove_submenu_page('options-general.php', 'global-weather-pro');
}

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

Where do I put this code?