code: def start(self):
      self.nextcalls = 0
  
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 5 for calling the TestStrategy obj's underlying member method code with example usage: obj.start() without return types