public virtual Object visitQuantifiedSentence(QuantifiedSentence sentence,
Object arg)
{
List<Variable> variables = new List<Variable>();
foreach (Variable var in sentence.getVariables())
{
variables.Add((Variable)var.accept(this, arg));
}
return new QuantifiedSentence(sentence.getQuantifier(), variables,
(Sentence)sentence.getQuantified().accept(this, arg));
}