static IntermediateGraph importGraph(String modelName, Onnx.ModelProto model) {
        Onnx.GraphProto onnxGraph = model.getGraph();

        IntermediateGraph intermediateGraph = new IntermediateGraph(modelName);
        importOperations(onnxGraph, intermediateGraph);
        verifyNoWarnings(intermediateGraph);
        verifyOutputTypes(onnxGraph, intermediateGraph);

        return intermediateGraph;
    }
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