code: def next(self):
      if self.p.datalines:
          txt = ",".join(
              [
                  "%04d" % len(self),
                  "%04d" % len(self.data0),
                  self.data.datetime.date(0).isoformat(),
              ]
          )
  
          print(txt)
  
file_path: backtrader/samples/memory-savings/memory-savings.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import argparse
  import sys
  import backtrader
  import backtrader.feeds
  import backtrader.indicators
  import backtrader.utils.flushfile
label_desc: Use image node_id 2 for calling the St obj's underlying member method code with example usage: obj.next() without return types