code: def get_history_window(
      self,
      assets,
      end_dt,
      bar_count,
      frequency,
      field,
      data_frequency=None,
      ffill=True,
  ):
      if field == "price":
          field = "close"
  
      return retry(
          action=self._get_history_window,
          attempts=self.attempts["get_history_window_attempts"],
          sleeptime=self.attempts["retry_sleeptime"],
          retry_exceptions=(ExchangeRequestError,),
          cleanup=lambda: log.warn("fetching history again."),
          args=(
              assets,
              end_dt,
              bar_count,
              frequency,
              field,
              data_frequency,
              ffill,
          ),
      )
  
imports: import abc
  import datetime
  import numpy
  import pandas
  from catalyst.assets._assets import TradingPair
  from catalyst.constants import LOG_LEVEL, AUTO_INGEST
  from catalyst.data.data_portal import DataPortal
  from catalyst.exchange.exchange_bundle import ExchangeBundle
  from catalyst.exchange.exchange_errors import ExchangeRequestError, PricingDataNotLoadedError
  from catalyst.exchange.utils.exchange_utils import resample_history_df, group_assets_by_exchange
  from catalyst.exchange.utils.datetime_utils import get_frequency, get_start_dt
  from logbook import Logger
  from redo import retry
label_desc: Use image node_id 3 for calling the DataPortalExchangeBase obj's underlying member method code with example usage: obj.get_history_window(assets, end_dt, bar_count, frequency, field, data_frequency, ffill) and returns: retry