How to Hide Feather Admin Menus

function plt_hide_feather_performance_menus() {
	//Hide "Feather".
	remove_menu_page('feather-performance');
	//Hide "Feather → Dashboard".
	remove_submenu_page('feather-performance', 'feather-performance');
	//Hide "Feather → Features".
	remove_submenu_page('feather-performance', 'feather-features');
	//Hide "Feather → Site Scan".
	remove_submenu_page('feather-performance', 'feather-scan');
	//Hide "Feather → Database".
	remove_submenu_page('feather-performance', 'feather-database');
	//Hide "Feather → Settings".
	remove_submenu_page('feather-performance', 'feather-settings');
	//Hide "Feather → About".
	remove_submenu_page('feather-performance', 'feather-about');
}

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

Where do I put this code?