Ben değiştirmek istiyorum

<lang class='brush:xhtml'>test</lang>

karşı

<pre class='brush:xhtml'>test</pre>

Benim böyle kodu.

<?php
$content="&lt;lang class='brush:xhtml'&gt;test&lt;/lang&gt;";
$pattern=array();
$replace=array();
$pattern[0]="/&lt;lang class=([A-Za-z='\":])* &lt;/";
$replace[0]="<pre $1>";

$pattern[1]="/&lt;lang&gt;/";
$replace[1]="</pre>";
echo preg_replace($pattern, $replace,$content);
?>

but it's not working. How karşı change my code or something wrong in my code ?