How to Disable REST API Access for Guests

function disable_rest_api_for_guests($access) {
    if(!is_user_logged_in()) {
        return new WP_Error(
            'rest_disabled',
            __('The REST API is disabled for guests.'),
            array('status' => 403)
        );
    }

    return $access;
}

add_filter('rest_authentication_errors','disable_rest_api_for_guests');