namespace SJK.Functional;
// [Obsolete]
// public class Cache<T> where T : class
// {
//     private T? _cache;
//     private Func<T> _provider;
//     private readonly Func<T, bool>? _isvalid;

//     public Cache(Func<T> provider, Func<T, bool>? isvalid = null)
//     {
//         _provider = provider;
//         _isvalid = isvalid;
//     }
//     public bool IsCached() => _cache is not null;
//     public T Value => _cache is null || (_isvalid is not null && !_isvalid(_cache)) ? _cache = _provider() : _cache;

// }