(
(let config (DataSource 'config))

# common types
(let ui64 (DataType 'Uint64))
(let str (DataType 'String))

# callable func
(let funcType (CallableType '() '(str) '(str) '(ui64)))
(let func (Udf 'SimpleUdf.Repeat))

# python udf
(let udfType (CallableType '() '(str) '(funcType) '(ui64)))
(let udfScript (String '@@
def new_string(func, x):
    return func(b'x', x) + b':' + func(b'y', x)
@@))
(let udf (ScriptUdf 'Python3 'new_string udfType udfScript))

# call udf
(let x (Uint64 '3))
(let result (Apply udf func x))

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

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