Meta Slider - Flex Slider Responsive Lightbox Vimeo

/**
 * INSTALLATION: this code should be pasted into your theme's functions.php file.
 *
 * USAGE:
 * Install 'Responsive Lightbox'. 
 * Add an image slide to your Meta Slider slideshow and enter the Vimeo URL in the URL field
 */
function metaslider_respoonsive_lightbox_vimeo($attributes, $slide, $slider_id) {

    if (strpos($attributes['href'], 'vimeo.com') !== false) {
        $attributes['rel'] = "lightbox-video-{$slide['id']}";
    }

    return $attributes;
}
add_filter('metaslider_flex_slider_anchor_attributes', 'metaslider_respoonsive_lightbox_vimeo', 10, 3);