anchor.diff:    confFile = pkgs.writeText "dante-sockd.conf" ''
       user.privileged: root
       user.unprivileged: dante
  +    logoutput: syslog
   
       ${cfg.config}
     '';
  
positive.code:       enable = mkEnableOption "Dante SOCKS proxy";
  
        config = mkOption {
          default     = null;
          type        = types.nullOr types.str;
          description = ''
            Contents of Dante's configuration file
            NOTE: user.privileged/user.unprivileged are set by the service
          '';
        };
      };
  
negative.code: 
    config = mkIf cfg.enable {
      assertions = [
        { assertion   = cfg.config != "";
          message     = "please provide Dante configuration file contents";
        }
      ];
  