code: def next(self):
      self.nextcalls += 1
  
      if self.p.main:
          dtstr = self.data.datetime.date(0).strftime("%Y-%m-%d")
          print("%s - %d - %f" % (dtstr, len(self), self.ind[0]))
          pstr = ", ".join(
              str(x)
              for x in [
                  self.data.open[0],
                  self.data.high[0],
                  self.data.low[0],
                  self.data.close[0],
              ]
          )
          print("%s - %d, %s" % (dtstr, len(self), pstr))
  
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 4 for calling the TestStrategy obj's underlying member method code with example usage: obj.next() without return types