mrb_class_get_id(mrb_state *mrb, mrb_sym name)
{
  return mrb_class_get_under_id(mrb, mrb->object_class, name);
}
mrb_class_get_id(mrb_state *mrb, mrb_sym name)
{
  return mrb_class_get_under_id(mrb, mrb->object_class, name);
}