public static IEnumerable <ITree <TSource> > ToTree <TSource, TKey>(this IEnumerable <TSource> source,
Func <TSource, TKey> keySelector,
Func <TSource, TKey> parentKeySelector)
{
if (source == null)
{
throw new ArgumentNullException(nameof(source));
}
if (keySelector == null)
{
throw new ArgumentNullException(nameof(keySelector));
}
if (parentKeySelector == null)
{
throw new ArgumentNullException(nameof(parentKeySelector));
}
return(TreeCollection.CreateTree(source, keySelector, parentKeySelector));
}