presto-main/src/main/java/io/prestosql/operator/scalar/annotations/ScalarFromAnnotationsParser.java/ScalarFromAnnotationsParser/parseFunctionDefinitions
class ScalarFromAnnotationsParser:    public static List<SqlScalarFunction> parseFunctionDefinitions(Class<?> clazz)
    {
        ImmutableList.Builder<SqlScalarFunction> builder = ImmutableList.builder();
        for (ScalarHeaderAndMethods methods : findScalarsInFunctionSetClass(clazz)) {
            // Non-static function only makes sense in classes annotated with @ScalarFunction or @ScalarOperator.
            builder.add(parseParametricScalar(methods, Optional.empty()));
        }
        return builder.build();
    }