@Override
 public String toString() {
   return ListUtils.toString(this);
 }
 @Override
 public IStrategoTerm toStrategoTerm(ITermFactory factory) {
   return ListUtils.toStrategoTerm(this, factory);
 }
 @Override
 public boolean equals(Object obj) {
   return ListUtils.equals(this, obj);
 }
 @Override
 public int hashCode() {
   return ListUtils.hashCode(this);
 }