//pretty print
public override void Print(PrettyPrinter printer)
{
printer.Println("OpenDerived_Unknown (");
using (printer.IndentCookie()) {
printer.Print("openDerivedString = "); OpenDerivedString.PrintEx(printer); printer.Println();
printer.Print("openString = "); OpenString.PrintEx(printer); printer.Println();
}
printer.Print(")");
}
