code: def __init__(self, frequency, maxLen=None):
      super(BarFeed, self).__init__(frequency, maxLen)
  
      self.__bars = {}
      self.__nextPos = {}
      self.__started = False
      self.__currDateTime = None
  
file_path: pyalgotrade/pyalgotrade/barfeed/membf.py
imports: import six
  from pyalgotrade import barfeed
  from pyalgotrade import bar
  from pyalgotrade import utils
label_desc: Use image node_id 1 to create a new BarFeed object from inherited base classes: barfeed with example: obj = BarFeed(frequency, maxLen)