code: def bundle_to_csv(self):
      exchange_name = "poloniex"
      data_frequency = "minute"
      period = "2017-01"
      symbol = "eth_btc"
  
      exchange = get_exchange(exchange_name)
      asset = exchange.get_asset(symbol)
  
      path = get_bcolz_chunk(
          exchange_name=exchange.name,
          symbol=asset.symbol,
          data_frequency=data_frequency,
          period=period,
      )
      self._bundle_to_csv(
          asset=asset,
          exchange_name=exchange.name,
          data_frequency=data_frequency,
          path=path,
          filename=period,
      )
      pass
  
imports: import os
  import tempfile
  from logging import getLogger
  import pandas
  from catalyst.exchange.exchange_bcolz import BcolzExchangeBarReader, BcolzExchangeBarWriter
  from catalyst.exchange.exchange_bundle import ExchangeBundle, BUNDLE_NAME_TEMPLATE
  from catalyst.exchange.utils.bundle_utils import get_bcolz_chunk, get_df_from_arrays
  from catalyst.exchange.utils.datetime_utils import get_start_dt
  from catalyst.exchange.utils.exchange_utils import get_exchange_folder
  from catalyst.exchange.utils.factory import get_exchange
  from catalyst.exchange.utils.stats_utils import df_to_string
  from catalyst.utils.paths import ensure_directory
label_desc: Use image node_id 13 for calling the TestExchangeBundle obj's underlying member method code with example usage: obj.bundle_to_csv() without return types