class_docstr: A :class:`pyalgotrade.stratanalyzer.StrategyAnalyzer` that calculates
  max. drawdown and longest drawdown duration for the portfolio.
code: def calculateEquity(self, strat):
      return strat.getBroker().getEquity()
  
file_path: pyalgotrade/pyalgotrade/stratanalyzer/drawdown.py
imports: from pyalgotrade import stratanalyzer
  import datetime
label_desc: Use image node_id 2 for calling the DrawDown obj's underlying member method code with example usage: obj.calculateEquity(strat) and returns: strat