static IEnumerable<IAbsoluteDirectoryPath> ExistingMods(IAbsoluteDirectoryPath[] paths, params string[] mods) {
return paths.Any()
? mods.Select(
x => paths.Select(path => path.GetChildDirectoryWithName(x)).FirstOrDefault(p => p.Exists))
.Where(x => x != null)
: Enumerable.Empty<IAbsoluteDirectoryPath>();
}
