presto-main/src/main/java/io/prestosql/sql/planner/Partitioning.java/Translator/Translator
class Translator:        public Translator(
                Function<Symbol, Optional<Symbol>> columnTranslator,
                Function<Symbol, Optional<NullableValue>> constantTranslator,
                Function<Expression, Optional<Symbol>> expressionTranslator)
        {
            this.columnTranslator = requireNonNull(columnTranslator, "columnTranslator is null");
            this.constantTranslator = requireNonNull(constantTranslator, "constantTranslator is null");
            this.expressionTranslator = requireNonNull(expressionTranslator, "expressionTranslator is null");
        }