anchor.diff:  let
     cfg = config.services.dd-agent;
   
  -  datadog-conf = pkgs.runCommand "datadog.conf" {} ''
  +  datadog_conf = pkgs.runCommand "datadog.conf" {} ''
       sed -e 's|^api_key:|api_key: ${cfg.api_key}|' ${optionalString (cfg.hostname != null)
         "-e 's|^#hostname: mymachine.mydomain|hostname: ${cfg.hostname}|'"
       } ${pkgs.dd-agent}/etc/dd-agent/datadog.conf.example > $out
  
positive.code: 
      systemd.services.dd-agent = {
        description = "Datadog agent monitor";
        path = [ pkgs."dd-agent" ];
        wantedBy = [ "multi-user.target" ];
        serviceConfig = {
          ExecStart = "${pkgs.dd-agent}/bin/dd-agent foreground";
          User = "dd-agent";
          Group = "dd-agent";
        };
        restartTriggers = [ pkgs.dd-agent ];
      };
    };
  }
  
negative.code:   };
  
    config = mkIf cfg.enable {
      environment.etc = [ { source = datadog_conf; target = "dd-agent/datadog.conf"; } ];
      environment.systemPackages = [ pkgs."dd-agent" pkgs.sysstat pkgs.procps ];
  
      users.extraUsers."dd-agent" = {
        description = "Datadog Agent User";
  