public function getLastChild()
	{
		if ( ! $this->hasChildren()) {
			return null;
		}
		$right = $this->getRightValue() - 1;

		$searchCondition = $this->repository->createSearchCondition()
				->rightEqualsTo($right);

		$lastChild = $this->repository->search($searchCondition);
		if ( ! isset($lastChild[0])) {
			$dump = static::dump($this);
			throw new Exception\InvalidStructure("Could not find the last child of {$dump} but it must exist");
		}
		$lastChild = $lastChild[0];
		
		return $lastChild;
	}