code: def drawdown_start(self, return_date=False):
          
  
          # Thank you @cᴏʟᴅsᴘᴇᴇᴅ
          # https://stackoverflow.com/a/47892766/7954504
          dd = self.drawdown_idx()
          mask = nancumsum(dd == nanmin(dd.min)).astype(bool)
          start = dd.mask(mask)[::-1].idxmax()
          if return_date:
              return start.date()
          return start
docs: The date of the peak at which most severe drawdown began.
  
          Parameters
          ----------
          return_date : bool, default False
              If True, return a `datetime.date` object.
              If False, return a Pandas Timestamp object.
  
          Returns
          -------
          datetime.date or pandas._libs.tslib.Timestamp