code: def sendKeepAlive(self):
      logger.debug("Sending pusher:ping.")
      self.getWSClient().sendPing()
  
imports: import json
  from six.moves.urllib.parse import urlencode
  import pyalgotrade
  from pyalgotrade.websocket import client
  import pyalgotrade.logger
label_desc: Use image node_id 2 for calling the PingKeepAliveMgr obj's underlying member method code with example usage: obj.sendKeepAlive() without return types