Add revisions for portfolio items

HI, i ADDED THE CODE BUT i AM GETTING THE FOLLOWING ERROR WHEN i OPEN MY WEBSITE:

Fatal error: Call to undefined function add_filter() in /home/storage/2/69/39/tenstep/public_html/tenstep/wp-includes/functions.php on line 5175

Below is the last few lines of code from the functions.php file located in the wp-includes file. Am I missing something?

Thanks,
John

—————————————–
<?php
}

/**
* Parses and formats a MySQL datetime (Y-m-d H:i:s) for ISO8601/RFC3339.
*
* Explicitly strips timezones, as datetimes are not saved with any timezone
* information. Including any information on the offset could be misleading.
*
* @since 4.4.0
*
* @param string $date_string Date string to parse and format.
* @return string Date formatted for ISO8601/RFC3339.
*/
function mysql_to_rfc3339( $date_string ) {
$formatted = mysql2date( ‘c’, $date_string, false );

// Strip timezone information
return preg_replace( ‘/(?:Z|[+-]\d{2}(?::\d{2})?)$/’, ”, $formatted );
}

add_filter( ‘avf_portfolio_cpt_args’, ‘enfold_customization_revisions’, 1 );
function enfold_customization_revisions( $args ) {
$args[‘supports’] = array( ‘title’, ‘thumbnail’, ‘excerpt’, ‘editor’, ‘comments’, ‘revisions’ );
return $args;
}
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Morining Rikard, I hve added the access information in the private content section.

Thanks,
John

Ismael,
Thanks for helping with this issue! It is now working perfectly!

Regards,
John