private Lazy <int> GetTreeCount()
{
if (null != Childrens && Childrens.Count == 0)
{
return(new Lazy <int>(() => 1));
}
var l = new Lazy <int>(() => 1 + (Childrens?.Select(x => x.TreeCount.Value)?.Sum()
?? 0));
return(l);
}