Create Post Cards with Python

I’m creating posts in Ghost using Python via the admin API, which works quite well. For simplifying things I’m posting the content as HTML ( and let Ghost convert it into Mobiledoc.

Now I would love to add an Email card to the post, but I’m not sure how to achieve that. Either I can do this via the html field (what markup to use?) or I have to start using Mobiledoc which doesn’t seem to be so easy with Python (missing library - at least I didn’t find any).

Are there any thoughts or advice how I could achieve what I want to do (without changing to JavaScript, I’d love to stay with Python)?