Unlisted option on creation of a new topic

Hi,
I’m interested in doing this via the discourse ruby gem (preferably) or some other automated way.

I can’t figure out the right argument to pass into the DiscourseClient#create_topic though, and it doesn’t appear to be in the documentation as a parameter in a plain curl call, or in the discourse-rails docs… I’ve also tried a few guesses like visible:false and unlisted:true Can anyone point me in the right direction or tell me it’s not a feature?