public void Add(Element elem)
{
if (Childrens == null) {
Childrens = new List<Element>();
}
Childrens.Add(elem);
}
static void Main(string[] args)
{
MEnumerable collection = new MEnumerable();
var elem1 = new Element(new User(){Name ="qwerty", Birthday = DateTime.UtcNow.AddYears(-20)});
elem1.Add(new Element(new User() { Name = "asddd", Birthday = DateTime.UtcNow.AddYears(-6) }));
elem1.Add(new Element(new User() { Name = "zxczxc", Birthday = DateTime.UtcNow.AddYears(-5) }));
elem1.Add(new Element(new User() { Name = "jgjfjdl", Birthday = DateTime.UtcNow.AddYears(-2) }));
elem1.Add(new Element(new User() { Name = "mcmzxc", Birthday = DateTime.UtcNow.AddYears(-1) }));
var elem2 = new Element(new User() { Name = "123123", Birthday = DateTime.UtcNow.AddYears(-22) });
elem2.Add(new Element(new User() { Name = "23465", Birthday = DateTime.UtcNow.AddYears(-1) }));
collection.Add(elem1);
collection.Add(elem2);
foreach (var elem in collection) {
Console.WriteLine(elem.User);
}
Console.ReadKey();
}