code: def prenext(self):
      pass
  
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import datetime
  import os
  import os.path
  import sys
  import backtrader
  import backtrader.utils.flushfile
  from backtrader.metabase import ParamsBase
label_desc: Use image node_id 2 for calling the TestStrategy obj's underlying member method code with example usage: obj.prenext() without return types