private static Optional<Onnx.NodeProto> getNodeFromGraphNames(String nodeName, Onnx.GraphProto graph) {
        return graph.getNodeList().stream().filter(node -> node.getName().equals(nodeName)).findFirst();
    }
Converts an ONNX graph to a Vespa IntermediateGraph which is the basis
for generating Vespa ranking expressions.

@author lesters
model-integration/src/main/java/ai/vespa/rankingexpression/importer/onnx/GraphImporter.java