xbt_dynar_get_cpy(keys, i, &thiskey);
xbt_dynar_get_cpy(lens, i, &thislen);
/* search the dict of next level */
TRY {
nextlevel = xbt_dict_get_ext(thislevel, thiskey, thislen);
xbt_dynar_get_cpy(keys, i, &thiskey);
xbt_dynar_get_cpy(lens, i, &thislen);
/* search the dict of next level */
TRY {
nextlevel = xbt_dict_get_ext(thislevel, thiskey, thislen);