code: def next(self):
      for trade in self._owner._tradespending:
          if trade.data not in self.ddatas:
              continue
  
          if not trade.isclosed:
              continue
  
          self.lines[trade.data._id - 1][0] = trade.pnl
  
file_path: backtrader/backtrader/observers/trades.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import uuid
  from ..None import Observer
  from ..utils.py3 import with_metaclass
  from ..trade import Trade
label_desc: Use image node_id 1 for calling the DataTrades obj's underlying member method code with example usage: obj.next() without return types