Exclude past events from Modern Tribe's Events Calendar plugin when rebuilding Relevanssi's search index

functions.php

add_filter('relevanssi_do_not_index', 'mytheme_noindex_old_events', 10, 2);
function mytheme_noindex_old_events($block, $post_id) {
    $events_to_exclude;
    $result = wp_cache_get( 'old_events' );
    if ( false === $result ) {
    	$events = tribe_get_events( array(
    		'start_date'     => date( 'Y-m-d H:i:s', strtotime( '-5 years' ) ),
    		'end_date'       => date( 'Y-m-d H:i:s', strtotime( '-1 day' ) ),
    		'eventDisplay'   => 'custom',
    		'posts_per_page' => 99999
    	));
    	foreach ($events as $event) {
        	$events_to_exclude[] = $event->ID;
    	}
    	$result = $events_to_exclude;
    	wp_cache_set( 'old_events', $result );
    } 
	if (in_array($post_id, $result)) $block = true;
    return $block;
}