code: def _daycount(self):
      dt = self.data.datetime.date()
      if dt > self.dtlast:
          self.days += 1
          self.dtlast = dt
  
file_path: backtrader/samples/relative-volume/relvolbybar.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import collections
  import datetime
  import math
  import backtrader
label_desc: Use image node_id 4 for calling the RelativeVolumeByBar obj's underlying member method code with example usage: obj._daycount() without return types