@Override
	public String toString(){
		if (binaryRule != null){
			return binaryRule.toString() + " score: " + score + " split: " + split + " leftRank: " + leftRank + " rightRank: " + rightRank;
		} else if (unaryRule != null){
			return unaryRule.toString() + " score: " + score + " split: " + split;
		} else {
			return "score: " + score + " split: " + split;
		}

	}