code: def main():
      watcher = WatcherBase()
      stream = watcher.create_stream(expr="lambda vars:vars.x**2")
  
      zmq_pub = ZmqStream(
          for_write=True, stream_name="ZmqPub", console_debug=True
      )
      zmq_pub.subscribe(stream)
  
      for i in range(5):
          watcher.observe(x=i)
      input("paused")
  
label_desc: Use image node_id 1 for calling a global function with example usage: main() without return types