public function getEntity($className, $id)
    {
        if (isset($this->entities[$className]) && isset($this->entities[$className][$id])) {
            return $this->entities[$className][$id];
        }

        if (isset($this->stashedEntities[$className]) && isset($this->stashedEntities[$className][$id])) {
            return $this->stashedEntities[$className][$id];
        }

        return null;
    }