class_docstr: Minimal interface to avoid errors when trade tries to get information from
  the data during the test
code: def __len__(self):
      return 0
  
file_path: backtrader/tests/test_trade.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import testcommon
  import backtrader
  from backtrader import trade
label_desc: Use image node_id 1 for calling the FakeData obj's underlying member method code with example usage: obj.__len__() and returns: int