presto-ml/src/main/java/io/prestosql/plugin/ml/LearnLibSvmVarcharClassifierAggregation.java/LearnLibSvmVarcharClassifierAggregation/input
class LearnLibSvmVarcharClassifierAggregation:    @InputFunction
    public static void input(
            @AggregationState LearnState state,
            @SqlType(VARCHAR) Slice label,
            @SqlType("map(bigint,double)") Block features,
            @SqlType(VARCHAR) Slice parameters)
    {
        state.getLabels().add((double) state.enumerateLabel(label.toStringUtf8()));
        FeatureVector featureVector = ModelUtils.toFeatures(features);
        state.addMemoryUsage(featureVector.getEstimatedSize());
        state.getFeatureVectors().add(featureVector);
        state.setParameters(parameters);
    }