anchor.diff:  
     config = mkIf cfg.enable {
   
  -    environment.systemPackages = [ pkgs.unbound ];
  +    environment.systemPackages = [ cfg.package ];
   
       users.users.unbound = {
         description = "unbound daemon user";
  
positive.code: 
        enable = mkEnableOption "Unbound domain name server";
  
        allowedAccess = mkOption {
          default = [ "127.0.0.0/24" ];
          type = types.listOf types.str;
  
negative.code:         mkdir -m 0755 -p ${stateDir}/dev/
          cp ${confFile} ${stateDir}/unbound.conf
          ${optionalString cfg.enableRootTrustAnchor ''
            ${cfg.package}/bin/unbound-anchor -a ${rootTrustAnchorFile} || echo "Root anchor updated!"
            chown unbound ${stateDir} ${rootTrustAnchorFile}
          ''}
          touch ${stateDir}/dev/random
  