@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		Tuple2 other = (Tuple2) obj;
		if (_1 == null) {
			if (other._1 != null)
				return false;
		} else if (!_1.equals(other._1))
			return false;
		if (_2 == null) {
			if (other._2 != null)
				return false;
		} else if (!_2.equals(other._2))
			return false;
		return true;
	}