anchor.diff:          type = types.submodule {
             options = {
               background = mkOption {
  -              type = types.string;
  +              type = types.str;
                 default = "#ffffff";
                 description = ''
                   Background color of the window. Only applications which do not cover
  
positive.code:   windowCommandModule = types.submodule {
      options = {
        command = mkOption {
          type = types.string;
          description = "i3wm command to execute.";
          example = "border pixel 1";
        };
  
negative.code:       };
  
        command = mkOption {
          type = types.str;
          default = "${cfg.package}/bin/i3bar";
          defaultText = "i3bar";
          description = "Command that will be used to start a bar.";
  