internal PocoIndex(PocoCache <T, S> cache, Func <S, U> paramfunc1)
{
_cache = cache;
_dict = new BiDictionaryOneToMany <T, U>(_cache.Keys.ToDictionary(a => a, a => paramfunc1(_cache.Get(a))));
_func = paramfunc1;
cache.AddChain(this);
}
