Parse error: syntax error, unexpected 'Expires' (T_STRING), expecting ')' in /home/public_html/wp-includes/functions.php on line 1081

i m facing this error in my WordPress site Parse error: syntax error, unexpected 'Expires' (T_STRING), expecting ')' in /home/public_html/wp-includes/functions.php on line 1081

here is the code

if ( $frag ) {
    $uri = substr($u
   expires Expires header.
     *     @type string $Cache-Control Cache-Control header.
     * }
     */
    $headers = (array) apply_filters( 'nocache_headers', $headers );
}

how to fix this?