code: def simple_periodic_send(bus):
      
      print("Starting to send a message every 200ms for 2s")
      msg = can.Message(arbitration_id=0x123, data=[1, 2, 3, 4, 5, 6], is_extended_id=False)
      task = bus.send_periodic(msg, 0.20)
      assert isinstance(task, can.CyclicSendTaskABC)
      time.sleep(2)
      task.stop()
      print("stopped cyclic send")
docs: Sends a message every 20ms with no explicit timeout
      Sleeps for 2 seconds then stops the task.