code: def start(self):
      if self.p.printout:
          txtfields = list()
          txtfields.append("Len")
          txtfields.append("Datetime")
          txtfields.append("Open")
          txtfields.append("High")
          txtfields.append("Low")
          txtfields.append("Close")
          txtfields.append("Volume")
          txtfields.append("OpenInterest")
          print(",".join(txtfields))
  
file_path: backtrader/samples/observer-benchmark/observer-benchmark.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import argparse
  import datetime
  import random
  import backtrader
label_desc: Use image node_id 2 for calling the St obj's underlying member method code with example usage: obj.start() without return types