code: def __getOrderSize(self, bars, hedgeRatio):
      cash = self.getBroker().getCash(False)
      price1 = bars[self.__i1].getAdjClose()
      price2 = bars[self.__i2].getAdjClose()
      size1 = int(cash / (price1 + hedgeRatio * price2))
      size2 = int(size1 * hedgeRatio)
      return (size1, size2)
  
imports: from __future__ import print_function
  from pyalgotrade import strategy
  from pyalgotrade import dataseries
  from pyalgotrade.dataseries import aligned
  from pyalgotrade import plotter
  from pyalgotrade.barfeed import yahoofeed
  from pyalgotrade.stratanalyzer import sharpe
  import numpy
  import statsmodels.api
label_desc: Use image node_id 4 for calling the StatArb obj's underlying member method code with example usage: obj.__getOrderSize(bars, hedgeRatio) and returns: size1,  size2