code: async def clean(self):
          
          for x in self._running_asyncio_tasks:
              x.cancel()
          self._container_had_error = set()
          self._watching = set()
          self._running_asyncio_tasks = set()
docs: Close all the running tasks watching for a container timeout. All references to
              containers are removed: any attempt to was_killed after a call to clean() will return None.