PostGrid: Filter the classes for a postgrid links to make them open in a lightbox

gistfile1.txt

/**
 * Filter the classes for a postgrid links to make them open in a lightbox
 *
 * @since 1.5.0
 *
 * @param string  $classes  The string containing all of the classes for postgrid links
 */
function my_custom_postgrid_classes( $classes ){
	return 'mp-stacks-lightbox-link';
}
add_filter( 'mp_stacks_postgrid_grid_postlink_classes', 'my_custom_postgrid_classes' );