For the python SDK, is there somewhere where we document more "advance" composite transform operations? e.g. I've been stumbling with questions like "How do I use a transform that expects a PBegin in a composite transform", "What's the proper way to return multiple output pcollections?", "What's the proper way to typehint multiple output pcollections?"
ChatGPT helped me figure out the first question (use `pcoll.pipeline`), the second question I guessed and the third question I'm still unsure about. Tried looking for these answers in the documentation but might just be missing it. Best, Joey
