mrb_mod_dup(mrb_state *mrb, mrb_value self)
{
  mrb_value mod = mrb_obj_clone(mrb, self);
  MRB_UNSET_FROZEN_FLAG(mrb_obj_ptr(mod));
  return mod;
}
mrb_mod_dup(mrb_state *mrb, mrb_value self)
{
  mrb_value mod = mrb_obj_clone(mrb, self);
  MRB_UNSET_FROZEN_FLAG(mrb_obj_ptr(mod));
  return mod;
}