code: def test_day_of_month(self):
      dt = datetime(2007, 1, 1)
      offset = MonthEnd()
  
      result = dt + offset
      assert result == Timestamp(2007, 1, 31)
  
      result = result + offset
      assert result == Timestamp(2007, 2, 28)
  
imports: from __future__ import annotations
  from datetime import datetime
  import pytest
  from pandas._libs.tslibs import Timestamp
  from pandas._libs.tslibs.offsets import MonthBegin, MonthEnd, SemiMonthBegin, SemiMonthEnd
  from pandas import DatetimeIndex, Series, _testing
  from pandas.tests.tseries.offsets.common import assert_is_on_offset, assert_offset_equal
label_desc: Use image node_id 1 for calling the TestMonthEnd obj's underlying member method code with example usage: obj.test_day_of_month() without return types