code: def test_roundtrip_pickle(self, offset, offset2):
      def _check_roundtrip(obj):
          unpickled = tm.round_trip_pickle(obj)
          assert unpickled == obj
  
      _check_roundtrip(offset)
      _check_roundtrip(offset2)
      _check_roundtrip(offset * 2)
  
file_path: pandas/pandas/tests/tseries/offsets/test_custom_business_day.py
imports: from datetime import datetime, timedelta
  import numpy
  import pytest
  from pandas._libs.tslibs.offsets import CDay
  from pandas import _testing, read_pickle
  from pandas.tests.tseries.offsets.common import assert_offset_equal
  from pandas.tseries.holiday import USFederalHolidayCalendar
label_desc: Use image node_id 6 for calling the TestCustomBusinessDay obj's underlying member method code with example usage: obj.test_roundtrip_pickle(offset, offset2) without return types