code: def next(self):
      self.callcounter += 1
  
      txtfields = list()
      txtfields.append("%04d" % self.callcounter)
      txtfields.append("%04d" % len(self))
      txtfields.append("%04d" % len(self.data0))
      txtfields.append(self.data.datetime.datetime(0).isoformat())
      txtfields.append("%.2f" % self.data0.open[0])
      txtfields.append("%.2f" % self.data0.high[0])
      txtfields.append("%.2f" % self.data0.low[0])
      txtfields.append("%.2f" % self.data0.close[0])
      txtfields.append("%.2f" % self.data0.volume[0])
      txtfields.append("%.2f" % self.data0.openinterest[0])
      print(",".join(txtfields))
  
      if len(self.data) > self.lcontrol:
          print("- I could issue a buy order during the Opening")
  
      self.lcontrol = len(self.data)
  
file_path: backtrader/samples/daysteps/daysteps.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import argparse
  import backtrader
label_desc: Use image node_id 3 for calling the St obj's underlying member method code with example usage: obj.next() without return types