(
(let config (DataSource 'config))

# prepare python udf
(let i64 (DataType 'Int64))
(let udfType (CallableType '() '((ListType i64)) '((ListType i64))))
(let udfScript (String '@@
def h(input):
    def gen():
        for x in input:
            yield int(x + 42)
    return gen
@@))
(let udf (ScriptUdf 'Python3 'h udfType udfScript))

# call udf
(let result (Apply udf (AsList (Int64 '1) (Int64 '2) (Int64 '3))))

# output result with type
(let sink (DataSink 'result))
(let world (Write! world sink (Key) result '( '('type) )))

# finish
(return (Commit! world sink))
)