data_to_value
ret = data_to_value(state->cl_realm, obj, AU_CREF_REALM);
data_to_value(krb5_data *data, k5_json_object obj, const char *key);
ret = data_to_value(&princ->realm, tmp, AU_REALM);
ret = data_to_value(&part2->transited.tr_contents,