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