presto-main/src/main/java/io/prestosql/sql/planner/optimizations/ActualProperties.java/ActualProperties/translateConstants
class ActualProperties:    private Map<Symbol, NullableValue> translateConstants(Function<Symbol, Optional<Symbol>> translator)
    {
        Map<Symbol, NullableValue> translatedConstants = new HashMap<>();
        for (Map.Entry<Symbol, NullableValue> entry : constants.entrySet()) {
            Optional<Symbol> translatedKey = translator.apply(entry.getKey());
            if (translatedKey.isPresent()) {
                translatedConstants.put(translatedKey.get(), entry.getValue());
            }
        }
        return translatedConstants;
    }