AudioProcessorGraph addNode() needs "AudioProcessor"

There are several examples on the web where we add a AudioGraphIOProcessor to an AudioProcessorGraph.
However, XCode does not seem to appreciate:

    AudioProcessorGraph::AudioGraphIOProcessor* input =
    new AudioProcessorGraph::AudioGraphIOProcessor(
      AudioProcessorGraph::AudioGraphIOProcessor::audioInputNode);

with graph being a AudioProcessorGraph,

AudioProcessorGraph::Node::Ptr inputNodePtr = graph.addNode(input);

addNode() is expecting a std::unique_ptr<AudioProcessor>,
XCode says “no viable conversion”.

What am I missing?

std::unique_ptr<AudioProcessorGraph::AudioGraphIOProcessor> m_ioProcIn;

m_ioProcIn.reset (new AudioProcessorGraph::AudioGraphIOProcessor (AudioProcessorGraph::AudioGraphIOProcessor::audioInputNode));

Sorry, your answer may not be enough verbose for me. My problem is that in some examples I have seen, I can’t get addNode() working. But thanks to the great “AudioProcessorGraphTutorial”, I am sure to find the proper way!