static O cloneWithoutField(O o, S fieldToSkip) ctex {
  if (o == null) null;
  final O clone = nuObject(o.getClass());
  Class c = o.getClass();
  while (c != Object.class) {
    Field[] fields = c.getDeclaredFields();
    for (final Field field : fields) {
      if (eq(field.getName(), fieldToSkip)) continue;
      if ((field.getModifiers() & Modifier.STATIC) != 0) continue;
      field.setAccessible(true);
      field.set(clone, field.get(o));
    }
    c = c.getSuperclass();
  }
  return clone;
}