code: def __getstate__(self):
      return (
          self.__dateTime,
          self.__tradeId,
          self.__price,
          self.__amount,
      )
  
imports: import datetime
  import time
  from six.moves import queue
  from pyalgotrade import bar
  from pyalgotrade import barfeed
  from pyalgotrade import observer
  from pyalgotrade.bitstamp import common
  from pyalgotrade.bitstamp import wsclient
label_desc: Use image node_id 3 for calling the TradeBar obj's underlying member method code with example usage: obj.__getstate__() and returns: self,  self,  self,  self