addChild method
Implementation
TreeElement<T> addChild(T child) {
children ??= <TreeElement<T>>[];
var element = TreeElement(child, this);
children!.add(element);
return element;
}
TreeElement<T> addChild(T child) {
children ??= <TreeElement<T>>[];
var element = TreeElement(child, this);
children!.add(element);
return element;
}