I need help with rewriting this part of code (PHP > 5.3):

```
usort($arr,function($a,$b)use($var){return $a[$var]>$b[$var]?-1:$a[$var]!=$b[$var];});

```

to PHP 5.2:

```
usort($arr,create_function('$a, $b','global $var; return $a[$var]>$b[$var]?-1:$a[$var]!=$b[$var];'));

```

Now I've got an error:

```
PHP Notice: Undefined index: in file.php(23) : runtime-created function on line 1,

```

What should I do to fix it?