anchor.diff:  
           killer = mkOption {
             default = null; # default according to `man xautolock` is none
  -          example = "systemctl suspend";
  -          type = types.nullOr types.string;
  +          example = "${pkgs.systemd}/bin/systemctl suspend";
  +          type = types.nullOr types.str;
   
             description = ''
               The script to use when nothing has happend for as long as <option>killtime</option>
  
positive.code: 
          nowlocker = mkOption {
            default = null;
            example = "i3lock -i /path/to/img";
            type = types.nullOr types.string;
  
            description = ''
              The script to use when manually locking the computer with <command>xautolock -locknow</command>.
  
negative.code:         };
  
          locker = mkOption {
            default = "${pkgs.xlockmore}/bin/xlock"; # default according to `man xautolock`
            example = "${pkgs.i3lock}/bin/i3lock -i /path/to/img";
            type = types.str;
  
            description = ''
              The script to use when automatically locking the computer.
  