Featured image portfolio dimensions

Hi There!

Yigit helped me out at: https://kriesi.at/support/topic/featured-image-portfolio-dimensions/

I thought I had this one coverd, but when I place this code into my functions, it comes with a syntax error:

add_filter( 'avf_modify_thumb_size', 'enfold_customization_modify_thumb_size', 10, 1 );
function enfold_customization_modify_thumb_size( $size ) {
        $size['portfolio'] 		 	= array('width'=>495, 'height'=>400);		
	return $size;	
}

See the link to the screendump.
Can you give me a hint ;-)

Best Regards, Annelies