public interface IDataCollectionGroup<out K, out T> : IDataCollection<T>, IReadOnlyList<T>, IReadOnlyCollection<T>, IEnumerable<T>, IEnumerable, INotifyCollectionChanged where K : class where T : class?

Public Interface IDataCollectionGroup(Of Out K As Class, Out T As Class)
    Inherits IDataCollection(Of T), IReadOnlyList(Of T), IReadOnlyCollection(Of T), IEnumerable(Of T), IEnumerable, INotifyCollectionChanged