code: def update_metadata(self, writer, start_dt, end_dt):
      pass
  
imports: import os
  import shutil
  from datetime import timedelta
  from functools import partial
  from itertools import chain
  from operator import is_not
  import numpy
  import pandas
  import pytz
  from catalyst import get_calendar
  from catalyst.assets._assets import TradingPair
  from catalyst.constants import DATE_TIME_FORMAT, AUTO_INGEST
  from catalyst.constants import LOG_LEVEL
  from catalyst.data.minute_bars import BcolzMinuteOverlappingData, BcolzMinuteBarMetadata
  from catalyst.exchange.exchange_bcolz import BcolzExchangeBarReader, BcolzExchangeBarWriter
  from catalyst.exchange.exchange_errors import EmptyValuesInBundleError, TempBundleNotFoundError, NoDataAvailableOnExchange, PricingDataNotLoadedError, DataCorruptionError, PricingDataValueError
  from catalyst.exchange.utils.bundle_utils import range_in_bundle, get_bcolz_chunk, get_df_from_arrays, get_assets
  from catalyst.exchange.utils.datetime_utils import get_start_dt, get_period_label, get_month_start_end, get_year_start_end
  from catalyst.exchange.utils.exchange_utils import get_exchange_folder, save_exchange_symbols, mixin_market_params, get_catalyst_symbol
  from catalyst.utils.cli import maybe_show_progress
  from catalyst.utils.paths import ensure_directory
  from logbook import Logger
  from pytz import UTC
  from six import itervalues
label_desc: Use image node_id 3 for calling the ExchangeBundle obj's underlying member method code with example usage: obj.update_metadata(writer, start_dt, end_dt) without return types