findNodeByKey method
Must be overriden by composed types. (See example implementation: ValueCompositionLogicalOperatorNode)
Implementation
@override
DartBlockValueTreeBooleanNode? findNodeByKey(String key) {
  if (key == nodeKey) {
    return this;
  } else {
    return leftChild?.findNodeByKey(key) ?? rightChild?.findNodeByKey(key);
  }
}