addChild: Add a child at a point in the tree.
Description
Add a child at a point in the tree.
Usage
addChild(self, private, id, data)
Arguments
self
The point in the tree where the child should be added.
private
The private part of the tree.
id
The id of the node that should be added.
data
The data of the node that should be added.
Value
invisible the new node that was created.