code: def shutdown(self):
  		
  		with self.lock:
  			self.pool.inqueue.put(StopIteration)   # Stop the pool workers
  			self.waitqueue.put(StopIteration)      # Stop the input_feeder
  			_iterqueue(self.waitqueue) >> item[-1] # Exhaust the waitqueue
  			self.closed = True
  		self.join()
docs: Shut down the Executor.  Suspend all waiting jobs.
  		
  		Running workers will terminate after finishing their current job items.
  		The call will block until all workers are terminated.