anchor.diff:          testScript = { nodes }:
             let
               esPort = toString nodes.parsedmarc.config.services.elasticsearch.port;
  +            valueObject = lib.optionalString (lib.versionAtLeast nodes.parsedmarc.config.services.elasticsearch.package.version "7") ".value";
             in ''
               mail.start()
               mail.wait_for_unit("postfix.service")
  
positive.code:       testScript = { nodes }:
          let
            esPort = toString nodes.parsedmarc.config.services.elasticsearch.port;
          in ''
            parsedmarc.start()
            parsedmarc.wait_for_unit("postfix.service")
  
negative.code:                 };
                };
  
                services.elasticsearch.package = pkgs.elasticsearch-oss;
  
                environment.systemPackages = [
                  pkgs.jq
  