map_val_t ll_cas (list_t *ll, map_key_t key, map_val_t expected_val, map_val_t new_val);
map_val_t ll_lookup (list_t *ll, map_key_t key);
map_val_t ll_remove (list_t *ll, map_key_t key);
-map_val_t ll_count (list_t *ll);
+size_t ll_count (list_t *ll);
void ll_print (list_t *ll);
void ll_free (list_t *ll);
map_key_t ll_min_key (list_t *sl);