static ImportedModel convertModel(String name, String source, Onnx.ModelProto modelProto, ImportedMlModel.ModelType modelType) {
         IntermediateGraph graph = GraphImporter.importGraph(name, modelProto);
         return convertIntermediateGraphToModel(graph, source, modelType);
    }
Converts a ONNX model into a ranking expression and set of constants.

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