Option_FilterZ ret_hu_conv = Option_FilterZ.constr_from_ptr(ret);
ret_hu_conv.ptrs_to.add(ret_hu_conv);
ret_hu_conv.ptrs_to.add(o);
Option_FilterZ ret_hu_conv = Option_FilterZ.constr_from_ptr(ret);
ret_hu_conv.ptrs_to.add(ret_hu_conv);
ret_hu_conv.ptrs_to.add(o);