public void SetLeft(T data)
 {
     _left = new BinaryTree <T>(data, this);
 }
 public void SetRight(T data)
 {
     _right = new BinaryTree <T>(data, this);
 }
 private BinaryTree(T data, BinaryTree <T> parent)
     : this(data)
 {
     _parent = parent;
 }