public function findAssociationPerformancelevelByID($id)
    {
        $performancelevels = $this->findAssociationPerformancelevels()->getPerformancelevels();

        $performancelevels->rewind();

        while ($performancelevels->valid()) {
            $performancelevel = $performancelevels->current();
            if ($performancelevel->getID() == $id) {
                return $performancelevel;
            }

            $performancelevels->next();
        }
    }