code: def update(self, dateTime, low, high):
      assert low <= high
      self.__lastLow = low
      self.__lastDateTime = dateTime
  
      if self.__highWatermark is None or high >= self.__highWatermark:
          self.__highWatermark = high
          self.__lowWatermark = low
          self.__highDateTime = dateTime
      else:
          self.__lowWatermark = min(self.__lowWatermark, low)
  
file_path: pyalgotrade/pyalgotrade/stratanalyzer/drawdown.py
imports: from pyalgotrade import stratanalyzer
  import datetime
label_desc: Use image node_id 5 for calling the DrawDownHelper obj's underlying member method code with example usage: obj.update(dateTime, low, high) without return types