The /e modifier is deprecated error

I need a little help. Because preg_replace is deprecated, I have to convert all my preg_replace to preg_replace_callback...

What I've tried:

Change:

 function getItem( $item, $tmp ) {


        retu preg_replace('/{([A-Za-z0-9_]+)}/e', '$item["$1"]', $tmp);

    }

To:

function getItem( $item, $tmp ) {

        retu preg_replace_callback('/{([A-Za-z0-9_]+)}/', function ($m){retu $item[$m[1]];},$tmp);


    }

Error:

Notice: Undefined variable: item in /home/merttugoto/public_html/admin/inc/dynamic.cls.php on line 129