private static Dictionary <int, ChallengeBase> LoadChallenges()
{
var context = new CollectibleAssemblyLoadContext();
var fs = new PhysicalFileSystem();
UPath basePath = fs.ConvertPathFromInternal(AppDomain.CurrentDomain.BaseDirectory);
var challenges = fs.EnumerateFileEntries(basePath, "Day*.dll")
.Select(entry => LoadChallenge(entry, context))
.ToDictionary(k => k.Day, v => v);
return(challenges);