code: def testNoDrawDown1(self):
      helper = drawdown.DrawDownHelper()
      helper.update(datetime.datetime.now(), 10, 10)
      self.assertEqual(helper.getMaxDrawDown(), 0)
      self.assertEqual(helper.getCurrentDrawDown(), 0)
      self.assertEqual(helper.getDuration(), datetime.timedelta())
  
imports: import datetime
  from .None import common
  from .None import strategy_test
  from pyalgotrade.barfeed import yahoofeed
  from pyalgotrade.barfeed import membf
  from pyalgotrade.stratanalyzer import drawdown
  from pyalgotrade import broker
  from pyalgotrade import bar
label_desc: Use image node_id 1 for calling the DDHelperCase obj's underlying member method code with example usage: obj.testNoDrawDown1() without return types