using System;

using System.Collections.Generic;

using System.Linq;

​

namespace EnumerableImplementationExample

{

​

public class EnumerableComposite<T> : IEnumerable<T>

{

    private List<IEnumerable<T>> _items;

    public EnumerableComposite(IEnumerable<IEnumerable<T>> collections)

    {

        _collections = collections.ToList();

    public IEnumerator<T> GetEnumerator()

    {

        throw new NotImplementedException();

    }

    IEnumerator IEnumerable.GetEnumerator()

    {

        throw new NotImplementedException();

    }

}

public class Program

{

    public static void Main()

    {

        var list1 = new List<int> {1, 3, 5, 6, 7, 9};

        var list2 = new List<int> {0,5,4,3,9,13};

        var set1 = new HashSet<int> { 0,6,7,14,177,179};

        //var ec = new EnumerableComposite<int> { list1, list2, set1 };

    }

}

}