presto-ml/src/main/java/io/prestosql/plugin/ml/LearnClassifierAggregation.java/LearnClassifierAggregation/output
class LearnClassifierAggregation:    @OutputFunction("Classifier(bigint)")
    public static void output(@AggregationState LearnState state, BlockBuilder out)
    {
        LearnLibSvmClassifierAggregation.output(state, out);
    }