code: def reset(self):
      self.__pnl = 0.0
      self.__avgPrice = 0.0  # Volume weighted average price per share.
      self.__position = 0.0
      self.__commissions = 0.0
      self.__totalCommited = 0.0
  
imports: import math
  from pyalgotrade import stratanalyzer
  from pyalgotrade import observer
  from pyalgotrade import dataseries
label_desc: Use image node_id 2 for calling the PositionTracker obj's underlying member method code with example usage: obj.reset() without return types