code: def test_is_on_offset_nanoseconds(self, n, week, date, tz):
      # GH 18864
      # Make sure that nanoseconds don't trip up is_on_offset (and with it apply)
      offset = WeekOfMonth(n=n, week=week, weekday=0)
      ts = Timestamp(date, tz=tz)
      fast = offset.is_on_offset(ts)
      slow = (ts + offset) - offset == ts
      assert fast == slow
  
imports: from __future__ import annotations
  from datetime import datetime, timedelta
  import pytest
  from pandas._libs.tslibs import Timestamp
  from pandas._libs.tslibs.offsets import Day, LastWeekOfMonth, Week, WeekOfMonth
  import pandas._testing
  from pandas.tests.tseries.offsets.common import WeekDay, assert_is_on_offset, assert_offset_equal
label_desc: Use image node_id 5 for calling the TestWeekOfMonth obj's underlying member method code with example usage: obj.test_is_on_offset_nanoseconds(n, week, date, tz) without return types