code: def loadBars(
      self,
      instrument,
      timezone=None,
      fromDateTime=None,
      toDateTime=None,
  ):
      bars = self.__db.getBars(
          instrument,
          self.getFrequency(),
          timezone,
          fromDateTime,
          toDateTime,
      )
      self.addBarsFromSequence(instrument, bars)
  
imports: from pyalgotrade.barfeed import dbfeed
  from pyalgotrade.barfeed import membf
  from pyalgotrade import bar
  from pyalgotrade.utils import dt
  import sqlite3
  import os
label_desc: Use image node_id 4 for calling the Feed obj's underlying member method code with example usage: obj.loadBars(instrument, timezone, fromDateTime, toDateTime) without return types