@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (!(obj instanceof Production))
			return false;
		Production other = (Production) obj;
		if (lhs == null) {
			if (other.lhs != null)
				return false;
		} else if (!lhs.equals(other.lhs))
			return false;
		if (rhs == null) {
			if (other.rhs != null)
				return false;
		} else if (!rhs.equals(other.rhs))
			return false;
		//return origin == other.origin;
		//return true;
		return nr == other.nr;
	}