Tree<T>.insert ​

Inserts a new node into the tree. If no parent is specified, the new node becomes the root node. If a parent is specified, the new node is inserted as a child of the parent. Throws an error if a root node already exists and no parent is specified.

Parameters ​

valueT | TreeNode<T>: The value to be stored in the new node.

parentTreeNode<T>: The parent node of the new node.

Returns ​

TreeNode<T>

The new node.