code: def profitandloss(self, size, price, newprice):
      return 0
  
file_path: backtrader/tests/test_order.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import backtrader
  from backtrader import Order, Position
label_desc: Use image node_id 2 for calling the FakeCommInfo obj's underlying member method code with example usage: obj.profitandloss(size, price, newprice) and returns: int