}
public Object visitNotSentence(NotSentence notSentence, Object arg) {
Sentence negated = notSentence.getNegated();
return new NotSentence((Sentence) negated.accept(this, arg));
}
public Object visitConnectedSentence(ConnectedSentence sentence, Object arg) {
Sentence alpha = (Sentence) sentence.getFirst().accept(this, arg);
Sentence beta = (Sentence) sentence.getSecond().accept(this, arg);