在运行时，以下内容将在控制台中显示url列表并继续计算
payload =
[{url:..., title:...}, {url=..., title=...}]
main =
payload
|>List.map.url -- only takes the url
|>Debug.log" My list of URLs" -- pass the url list toDebug.logand return it
|> doSomething -- do something with the url list