{ config, lib, ... }: let inherit (lib) concatMapStringsSep mkOption; inherit (lib.types) listOf str; in { options = { protocols.rstp = mkOption { type = listOf str; description = '' List of interfaces on which Rapid Spanning Tree Protocol should be enabled. ''; }; netconf.xmls.protocols = mkOption { type = str; visible = false; readOnly = true; }; }; config.netconf.xmls.protocols = '' ${ concatMapStringsSep "" (intf: "${intf}") config.protocols.rstp } ''; }