anchor.diff:            };
           }
         )
  -      (lib.filterAttrs (name: instance: instance.onCalendar != null)
  +      (filterAttrs (name: instance: instance.onCalendar != null)
           cfg.instances);
     };
   
  
positive.code:     )
    ;
    addDefaults = settings: { backend = "btrfs-progs-sudo"; } // settings;
    mkConfigFile = settings: lib.concatStringsSep "\n" (attr2Lines (addDefaults settings));
    mkTestedConfigFile = name: settings:
      let
        configFile = pkgs.writeText "btrbk-${name}.conf" (mkConfigFile settings);
  
negative.code:         map
            (
              pair:
              mapAttrsToList
                (
                  childname: value:
                    [ "${pair.name} ${childname}" ] ++ (map (x: " " + x) (attr2Lines value))
  