--sub-lang en works flawlessly but 'subtitleslang': "en" failed

[kfei]

I can download an youtube video with subtitle via youtube_dl --sub-lang en directly.
But when I set the parameter 'subtitleslang': "en"and pass it to YoutubeDL from my own program, it fails and says:

WARNING: unable to download video subtitles for en: Unable to download webpage: HTTP Error 404: Not Found; please report this issue on https://yt-dl.org/bug . Be sure to call youtube-dl with the --verbose flag and include its complete output. Make sure you are using the latest version; type youtube-dl -U to update.

What's the difference between call youtube_dl directly and using YoutubeDL library?

For a quick reproduce: https://www.youtube.com/watch?v=FN10crzDOjk

[jaimeMF]

We changed the option for the subtitles some time ago, now you have to set the subtitleslangs params like in __init__.py, but it's now a list of languages, as said in the documentation of YoutubeDL, for example ['en', 'es'], we did the change to support the request of multiple languages (like --sub-lang es,en).
I'm closing the issue, since I think that is the problem, if it persists comment here and I'll reopen it. Thanks for the report.