}

    public void addDependencySuccessor(Node toNode) {
        dependencyNodes = dependencyNodes.addDependency(toNode);
        toNode.addDependencyPredecessor(this);
    }

    void addDependencyPredecessor(Node fromNode) {
        dependentNodes = dependentNodes.addDependencyPredecessors(fromNode);
        mutationInfo.addConsumer(fromNode);
    }