Collection to API as opposed to API to Collection

I have been using postman for a while now and built up a sizeable collection of end points for the system my company is building. What I would like to do is start using the API side of Postman to create the YAML formatted documentation. It seems though that I have to write it all from scratch? Is there a way to import my existing collection that will therefore build the yaml document to start me off. Then I can use the API from that point onwards to further build the collection.