How to use Kemono DMs in a postprocessor?

[a84r7a3rga76fg]

"format": "{dms[N]['body']}" doesn't work.

So it only works with "format": "{dms]}"? ~~That only gets one DM. How to get all DMs?~~ It puts every DM in a single file. Any way to split each DM into one file? Also, how do you convert it to a SHA1 value? It only says "None" with "archive-format": "_{subcategory}_{user}_{hash_sha1(dms)}"