code: def notify_order(self, order):
      if order.status == bt.Order.Completed:
          t = ""
          t += "{:02d}".format(next(self.opcounter))
          t += " {}".format(order.data.datetime.datetime())
          t += " BUY " * order.isbuy() or " SELL"
          t += " Size: {:+d} / Price: {:.2f}"
          print(t.format(order.executed.size, order.executed.price))
  
file_path: backtrader/samples/slippage/slippage.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import argparse
  import collections
  import datetime
  import itertools
  import backtrader
label_desc: Use image node_id 1 for calling the SlipSt obj's underlying member method code with example usage: obj.notify_order(order) without return types