code: def periodic(self, callback, interval) -> Periodic:
      return TornadoPeriodic(callback=callback, interval=interval)
  
file_path: perspective/python/perspective/perspective/client/tornado.py
imports: from tornado import ioloop
  from tornado.websocket import websocket_connect
  from .websocket import PerspectiveWebsocketClient, PerspectiveWebsocketConnection, Periodic
label_desc: Use image node_id 2 for calling the PerspectiveTornadoWebsocketConnection obj's underlying member method code with example usage: obj.periodic(callback, interval) and returns: TornadoPeriodic