code: def test_candles(self):
      exchange_population = 3
      asset_population = 3
  
      # exchanges = select_random_exchanges(
      #     population=exchange_population,
      #     features=['fetchOHLCV'],
      # )  # Type: list[Exchange]
      exchanges = list(get_exchanges(["binance"]).values())
      for exchange in exchanges:
          exchange.init()
  
          if (
              exchange.assets
              and len(exchange.assets) >= asset_population
          ):
              frequencies = exchange.get_candle_frequencies()
              freq = random.sample(frequencies, 1)[0]
  
              bar_count = random.randint(1, 10)
              end_dt = pd.Timestamp.utcnow().floor("1T")
              dt_range = pd.date_range(
                  end=end_dt, periods=bar_count, freq=freq
              )
              assets = select_random_assets(
                  exchange.assets, asset_population
              )
  
              candles = exchange.get_candles(
                  freq=freq,
                  assets=assets,
                  bar_count=bar_count,
                  start_dt=dt_range[0],
              )
  
              assert len(candles) == asset_population
  
          else:
              print(
                  "skipping exchange without assets {}".format(
                      exchange.name
                  )
              )
              exchange_population -= 1
      pass
  
imports: import json
  import os
  import random
  from logging import Logger, WARNING
  from time import sleep
  import pandas
  from catalyst.assets._assets import TradingPair
  from logbook import TestHandler
  from catalyst.exchange.exchange_errors import ExchangeRequestError
  from catalyst.exchange.exchange_execution import ExchangeLimitOrder
  from catalyst.exchange.utils.exchange_utils import get_exchange_folder
  from catalyst.exchange.utils.test_utils import select_random_exchanges, handle_exchange_error, select_random_assets
  from catalyst.testing import CatalystTestCase
  from catalyst.testing.fixtures import WithLogger
  from catalyst.exchange.utils.factory import get_exchanges, get_exchange
label_desc: Use image node_id 4 for calling the TestSuiteExchange obj's underlying member method code with example usage: obj.test_candles() without return types