code: def init_class_fixtures(cls):
      super(BcolzMinuteBarTestCase, cls).init_class_fixtures()
  
      cal = cls.trading_calendar.schedule.loc[
          TEST_CALENDAR_START:TEST_CALENDAR_STOP
      ]
  
      cls.market_opens = cal.market_open
      cls.market_closes = cal.market_close
  
      cls.test_calendar_start = cls.market_opens.index[0]
      cls.test_calendar_stop = cls.market_opens.index[-1]
  
imports: from datetime import timedelta
  import os
  from numpy import arange, array, int64, float64, full, nan, transpose, zeros
  from numpy.testing import assert_almost_equal, assert_array_equal
  from pandas import DataFrame, DatetimeIndex, Timestamp, Timedelta, NaT, date_range
  from zipline.data.bar_reader import NoDataForSid, NoDataOnDate
  from zipline.data.minute_bars import BcolzMinuteBarMetadata, BcolzMinuteBarWriter, BcolzMinuteBarReader, BcolzMinuteOverlappingData, US_EQUITIES_MINUTES_PER_DAY, BcolzMinuteWriterColumnMismatch, H5MinuteBarUpdateWriter, H5MinuteBarUpdateReader
  from zipline.testing.fixtures import WithAssetFinder, WithInstanceTmpDir, WithTradingCalendars, ZiplineTestCase
label_desc: Use image node_id 1 for calling the BcolzMinuteBarTestCase obj's underlying member method code with example usage: obj.init_class_fixtures(cls) without return types