code: async def wait_for_all_empty(self, *queues):
          
          matchers = [m for m in (q.waitForEmpty() for q in queues) if m is not None]
          while matchers:
              await self.wait_for_all(*matchers)
              matchers = [m for m in (q.waitForEmpty() for q in queues) if m is not None]
docs: Wait for multiple queues to be empty at the same time.
  
          Require delegate when calling from coroutines running in other containers