anchor.diff:                    mode = "3840x2160";
                     gamma = "1.0:0.909:0.833";
                     rate = "60.00";
  +                  rotate = "left";
                   };
                 };
                 hooks.postswitch = readFile ./work-postswitch.sh;
  
positive.code:     ${optionalString (config.gamma != "") "gamma ${config.gamma}"}
      ${optionalString (config.mode != "") "mode ${config.mode}"}
      ${optionalString (config.rate != "") "rate ${config.rate}"}
    '' else ''
      output ${name}
      off
  
negative.code:         description = "Output gamma configuration.";
          default = "";
          example = "1.0:0.909:0.833";
        };
  
        rotate = mkOption {
          type = types.nullOr (types.enum ["normal" "left" "right" "inverted"]);
          description = "Output rotate configuration.";
          default = null;
          example = "left";
        };
      };
    };
  