How to Hide Rest Routes – Custom Endpoints for WP REST API Admin Menus

function plt_hide_rest_routes_menus() {
	//Hide "Rest Routes".
	remove_menu_page('rest-routes-main');
	//Hide "Rest Routes → Dashboard".
	remove_submenu_page('rest-routes-main', 'rest-routes-main');
	//Hide "Rest Routes → Routes".
	remove_submenu_page('rest-routes-main', 'http://127.0.0.1/wp-admin/edit.php?post_type=rest-route');
	//Hide "Rest Routes → Add New Route".
	remove_submenu_page('rest-routes-main', 'rest-routes-add-new');
	//Hide "Rest Routes → Contact Us".
	remove_submenu_page('rest-routes-main', 'rest-routes-main-contact');
	//Hide "Rest Routes → Support Forum".
	remove_submenu_page('rest-routes-main', 'rest-routes-main-wp-support-forum');
	//Hide "Rest Routes → Upgrade".
	remove_submenu_page('rest-routes-main', 'rest-routes-main-pricing');
}

add_action('admin_menu', 'plt_hide_rest_routes_menus', 1000000000);

Where do I put this code?