Message 208952 - Python tracker

concurrent.futures.as_completed([f,f]) will yield f twice, then fail with a KeyError for a Future f which is not completed.

If the Future has already completed, as_completed([f,f]) will yield f once and does not trigger an exception.

What is the correct behaviour?
   as_completed( [f,f] ) -> yield f twice ?
   wait( [f,f], return_when=ALL_COMPLETED ) -> yield f twice ?