code: def get_next_item(self):
          
  
          # Try to pop something off the local input-queue.
  
          try:
              return self.__local_input_q.get(block=False)
          except queue.Empty:
              pass
  
          # Try to pop something off the external input-queue.
  
          return self.input_q.get(block=False)
docs: Override the default functionality to not only try to pull things 
          off the external input-queue, but to first try to pull things from a 
          local input-queue that we'll primarily depend on. We'll only use the 
          external input-queue to get the initial root-path (we could reuse it to 
          do the recursion, but it's more costly and prone to delay).