anchor.diff:          description = "Whether to enable the PCSC-Lite daemon.";
         };
   
  +      allowedUsers = mkOption {
  +        type = types.listOf types.str;
  +        default = [ ];
  +        description = ''
  +          A list of users who can access pcsclite backed devices.
  +        '';
  +      };
  +
  +      allowedGroups = mkOption {
  +        type = types.listOf types.str;
  +        default = [ ];
  +        description = ''
  +          A list of groups who can access pcsclite backed devices.
  +        '';
  +      };
       };
   
     };
  
positive.code: 
  let
    cfgFile = pkgs.writeText "reader.conf" "";
  in
  
  with lib;
  
negative.code:     systemd.services.pcscd = {
        description = "PCSC-Lite daemon";
        preStart = ''
          mkdir -p /var/lib/pcsc
          rm -Rf /var/lib/pcsc/drivers
          ln -s ${pkgs.ccid}/pcsc/drivers /var/lib/pcsc/
        '';
        serviceConfig = {
          Type = "forking";
  