presto-ml/src/main/java/io/prestosql/plugin/ml/FeatureUnitNormalizer.java/FeatureUnitNormalizer/FeatureUnitNormalizer
class FeatureUnitNormalizer:    public FeatureUnitNormalizer()
    {
        mins = new Int2DoubleOpenHashMap();
        maxs = new Int2DoubleOpenHashMap();

        mins.defaultReturnValue(Double.POSITIVE_INFINITY);
        maxs.defaultReturnValue(Double.NEGATIVE_INFINITY);
    }