public boolean equals(Object obj) {
if (this == obj) return true;
if (obj == null) return false;
if (getClass() != obj.getClass()) return false;
@SuppressWarnings("rawtypes")
Tuple other = (Tuple) obj;
if (first == null) {
if (other.first != null) return false;
} else if (!first.equals(other.first)) return false;
return true;
}
