anchor.diff:            ${if cfg.websocket.enable then ''--ws --ws.addr ${cfg.websocket.address} --ws.port ${toString cfg.websocket.port}'' else ""} \
             ${optionalString (cfg.websocket.apis != null) ''--ws.api ${lib.concatStringsSep "," cfg.websocket.apis}''} \
             ${optionalString cfg.metrics.enable ''--metrics --metrics.addr ${cfg.metrics.address} --metrics.port ${toString cfg.metrics.port}''} \
  +          --authrpc.addr ${cfg.authrpc.address} --authrpc.port ${toString cfg.authrpc.port} --authrpc.vhosts ${lib.concatStringsSep "," cfg.authrpc.vhosts} \
  +          ${if (cfg.authrpc.jwtsecret != "") then ''--authrpc.jwtsecret ${cfg.authrpc.jwtsecret}'' else ''--authrpc.jwtsecret ${dataDir}/geth/jwtsecret''} \
             ${lib.escapeShellArgs cfg.extraArgs} \
  -          --datadir /var/lib/goethereum/${gethName}/${if (cfg.network == null) then "mainnet" else cfg.network}
  +          --datadir ${dataDir}
         '';
       }))) eachGeth;
   
  
positive.code:       cfg.package
      ]) eachGeth);
  
      systemd.services = mapAttrs' (gethName: cfg: (
        nameValuePair "geth-${gethName}" (mkIf cfg.enable {
        description = "Go Ethereum node (${gethName})";
        wantedBy = [ "multi-user.target" ];
  
negative.code:           default = null;
            description = lib.mdDoc "APIs to enable over WebSocket";
            example = ["net" "eth"];
          };
        };
  
        authrpc = {
          enable = lib.mkEnableOption "Go Ethereum Auth RPC API";
          address = mkOption {
            type = types.str;
            default = "127.0.0.1";
            description = lib.mdDoc "Listen address of Go Ethereum Auth RPC API.";
          };
  
          port = mkOption {
            type = types.port;
            default = 8551;
            description = lib.mdDoc "Port number of Go Ethereum Auth RPC API.";
          };
  
          vhosts = mkOption {
            type = types.nullOr (types.listOf types.str);
            default = ["localhost"];
            description = lib.mdDoc "List of virtual hostnames from which to accept requests.";
            example = ["localhost" "geth.example.org"];
          };
  
          jwtsecret = mkOption {
            type = types.str;
            default = "";
            description = lib.mdDoc "Path to a JWT secret for authenticated RPC endpoint.";
            example = "/var/run/geth/jwtsecret";
          };
        };
  
  