anchor.diff:  
       forwardZonesRecurse = mkOption {
         type = types.attrs;
  -      example = { eth = "127.0.0.1:5353"; };
  +      example = { eth = "[::1]:5353"; };
         default = {};
         description = ''
           DNS zones to be forwarded to other recursive servers.
  
positive.code:     enable = mkEnableOption "PowerDNS Recursor, a recursive DNS server";
  
      dns.address = mkOption {
        type = types.str;
        default = "0.0.0.0";
        description = ''
          IP address Recursor DNS server will bind to.
        '';
      };
  
  
negative.code: 
      api.allowFrom = mkOption {
        type = types.listOf types.str;
        default = [ "127.0.0.1" "::1" ];
        example = [ "0.0.0.0/0" "::/0" ];
        description = ''
          IP address ranges of clients allowed to make API requests.
        '';
  