code: def pipe_worker(conn):
      d = conn.recv()
      print("[pipe_worker] got command", d)
      conn.send(b"ack")
      print("[pipe_worker] ack")
  
imports: import fiber
  import pickle
  import time
  import pytest
  import docker
  import collections
  import multiprocessing
  from fiber.queues import Pipe, SimpleQueue
  from fiber.socket import Socket
label_desc: Use image node_id 6 for calling a global function with example usage: pipe_worker(conn) without return types