code: def get_hub():
      
      try:
          hub = _local.hub
      except AttributeError:
          # The Hub can only be instantiated from the root fiber. No other fibers
          # can run until the Hub is there, so the root will always be the first
          # one to call get_hub().
          assert fibers.current().parent is None
          hub = _local.hub = Hub()
      return hub
docs: Return the instance of the hub.