"field missing " pydantic exception trying to use app.bsky.actor.put_preferences()

[RedactedCode]

I'm getting very confused trying to use app.bsky.actor.put_preferences() to try and manage muted words.
I'm trying to pass a dictionary of the form:

{ "actor_target": "all", "expires_at": None, "id": None, "targets": [ "tag", "content", ], "value": "aMutedWord", }
But I get a pydantic "field missing" error every time.

[MarshalX]

Pydantic error mentions the name of the missing field. Attach the error and the code