private Map<String, Double> addScores(Map<String, Double> first, Map<String, Double> second) {
		Map<String, Double> result = new HashMap<String, Double>();
		result.put(POS_TAG, 0.0D);
		result.put(NEG_TAG, 0.0D);
		double score = 0.0D;
		if (first.containsKey(POS_TAG) && second.containsKey(POS_TAG)) {
			score = first.get(POS_TAG) + second.get(POS_TAG);
			result.put(POS_TAG, score);
		}
		if (first.containsKey(NEG_TAG) && second.containsKey(NEG_TAG)) {
			score = first.get(NEG_TAG) + second.get(NEG_TAG);
			result.put(NEG_TAG, score);
		}
		return result;
	}