oliverdavies.uk/modules/opd_presentations/src/Presentation.php

<?php

declare(strict_types=1);

namespace Drupal\opd_presentations;

use Drupal\node\Entity\Node;
use Drupal\node\NodeInterface;

final class Presentation extends Node implements NodeInterface {

  public const NODE_TYPE = 'presentation';

  public function getPastEvents(): Events {
    $events = Events::fromEvents($this->get('field_events')->referencedEntities());

    $today = strtotime('today');

    return $events->filter(fn (Event $event) => $event->getEventDate() < $today);
  }

}