404 page returns a fatal error

I was just checking what my 404 page looks like when I noticed it returns an error.

Fatal error: Call to undefined function custom404_print404message() in/home/content/83/10131583/html/wp-content/themes/mantra/404.php on line 25

I’ve certainly not change any of the content – this is my 404 file.

‘<?php

/**

* The template for displaying 404 pages (Not Found).

*

* @package Cryout Creations

* @subpackage mantra

* @since mantra 0.5

*/

get_header(); ?>

<div id=”container”>

<div id=”content” role=”main”>

<div id=”post-0″ class=”post error404 not-found”>

<h1 class=”entry-title”><?php _e( ‘Not Found’, ‘mantra’ ); ?></h1>

<div class=”entry-content”>

<p><?php _e( ‘Apologies, but the page you requested could not be found. Perhaps searching will help.’, ‘mantra’ ); ?></p>

<?php get_search_form(); ?>

</div><!– .entry-content –>

</div><!– #post-0 –>

<?custom404_print404message();?>

</div><!– #content –>

<?php get_sidebar(); ?>

</div><!– #container –>

<script type=”text/javascript”>

// focus on search field after it has loaded

document.getElementById(‘s’) && document.getElementById(‘s’).focus();

</script>

<?php get_footer(); ?>’

Thank you