Set Deepth for each node in forest

public class TreeNode
    {
        public string Name { get; set; }
        public TreeNode ParrentNode { get; set; }
        public List<TreeNode> LstChildren { get; set; }
        public int Deep { get; set; }


        public void AddChildren(TreeNode node)
        {
            LstChildren.Add(node);
            node.ParrentNode = this;
        }
    }

#region tree


        public void SetTreeDeep(TreeNode current)
        {
            current.Deep = GetDeepth(current);
            if (!current.LstChildren.Any())
                return;


            foreach (var children in current.LstChildren)
            {
                SetTreeDeep(children);
            }
        }


        public int GetDeepth(TreeNode node)
        {
            if (node == null)
                return 0;

            if (node.LstChildren.Any())
            {
                var deepArr = node.LstChildren.Select(GetDeepth).ToList();
                var maxChildDeep = deepArr.Max() + 1;
                return maxChildDeep;
            }
            return 0;
        }


        #endregion

[TestMethod]
        public void SetTreeDeep()
        {
            //              root
            //             / | \
            //            t1 t2 t3
            //           / \   /  \
            //          t4  t5 t6 t7
            //             /  \     \
            //            8    9     t10    
            var nodeLst = new List<TreeNode>
                {
                    new TreeNode() {Name = "Root", LstChildren = new List<TreeNode>(), Deep = 0, ParrentNode = null},
                     new TreeNode() { Name = "T1", LstChildren = new List<TreeNode>(), Deep = 0 },
            new TreeNode() { Name = "T2", LstChildren = new List<TreeNode>(), Deep = 0 },
             new TreeNode() { Name = "T3", LstChildren = new List<TreeNode>(), Deep = 0 },
             new TreeNode() { Name = "T4", LstChildren = new List<TreeNode>(), Deep = 0 },
             new TreeNode() { Name = "T5", LstChildren = new List<TreeNode>(), Deep = 0 },
            new TreeNode() { Name = "T6", LstChildren = new List<TreeNode>(), Deep = 0 },
             new TreeNode() { Name = "T7", LstChildren = new List<TreeNode>(), Deep = 0 },
             new TreeNode() { Name = "T8", LstChildren = new List<TreeNode>(), Deep = 0 },
            new TreeNode() { Name = "T9", LstChildren = new List<TreeNode>(), Deep = 0 },
             new TreeNode() { Name = "T10", LstChildren = new List<TreeNode>(), Deep = 0 }
                };


            nodeLst[7].AddChildren(nodeLst[10]);
            nodeLst[3].AddChildren(nodeLst[6]);
            nodeLst[3].AddChildren(nodeLst[7]);
            nodeLst[0].AddChildren(nodeLst[3]);

            nodeLst[0].AddChildren(nodeLst[2]);

            nodeLst[5].AddChildren(nodeLst[8]);
            nodeLst[5].AddChildren(nodeLst[9]);
            nodeLst[1].AddChildren(nodeLst[4]);
            nodeLst[1].AddChildren(nodeLst[5]);
            nodeLst[0].AddChildren(nodeLst[1]);

            var stds = new SetTreeDeepSample();
            stds.SetTreeDeep(nodeLst[0]);


            var ret = String.Join(",", nodeLst.Select(n => n.Deep).ToArray());

//expected result :3,2,0,2,0,1,0,1,0,0,0

        }