How to Hide the "WDS Theme Switcher" Admin Menu

function plt_hide_wds_theme_switcher_menus() {
	//Hide the "WDS Theme Switcher" menu.
	remove_menu_page('wds-theme-switcher');
}

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

Where do I put this code?