DocumentRepository::findBy() not compatible with interface

<?php

use Doctrine\MongoDB\Connection;
use Doctrine\ODM\MongoDB\DocumentManager;
use Doctrine\ODM\MongoDB\Configuration;
use Documents\Event;

$manager = new DocumentManager(
    new Connection(...),
    new Configuration(...)
);

$manager->getRepository('Documents\Event');

public function findBy(array $criteria, array $orderBy = null, $limit = null, $offset = null);

public function findBy(array $criteria) { ... }