code: def testRollback1(self):
      assert CDay(10).rollback(datetime(2007, 12, 31)) == datetime(
          2007, 12, 31
      )
  
imports: from __future__ import annotations
  from datetime import date, datetime, timedelta
  import numpy
  import pytest
  from pandas._libs.tslibs.offsets import CBMonthBegin, CBMonthEnd, CDay
  import pandas._testing
  from pandas.tests.tseries.offsets.common import assert_is_on_offset, assert_offset_equal
  from pandas.tseries import offsets
label_desc: Use image node_id 4 for calling the TestCustomBusinessMonthBegin obj's underlying member method code with example usage: obj.testRollback1() without return types