code: def test_NDaysBeforeLastTradingDayOfMonth(self):
      for n in range(MAX_MONTH_RANGE):
          rule = NDaysBeforeLastTradingDayOfMonth(n)
          rule.cal = self.cal
          should_trigger = rule.should_trigger
          sessions = reversed(self.oct_sessions)
          for n_days_before, session in enumerate(sessions):
              for m in self.cal.minutes_for_session(session)[0:10]:
                  if should_trigger(m):
                      self.assertEqual(n_days_before, n)
                  else:
                      self.assertNotEqual(n_days_before, n)
  
imports: import datetime
  from inspect import isabstract
  import random
  from unittest import TestCase
  import warnings
  from nose_parameterized import parameterized
  import pandas
  from six import iteritems
  from six.moves import range, map
  import catalyst.utils.events
  from catalyst.utils.calendars import get_calendar
  from catalyst.utils.events import EventRule, StatelessRule, Always, Never, AfterOpen, ComposedRule, BeforeClose, NotHalfDay, NthTradingDayOfWeek, NDaysBeforeLastTradingDayOfWeek, NthTradingDayOfMonth, NDaysBeforeLastTradingDayOfMonth, StatefulRule, OncePerDay, _build_offset, _build_date, _build_time, EventManager, Event, MAX_MONTH_RANGE, MAX_WEEK_RANGE, TradingDayOfMonthRule, TradingDayOfWeekRule
label_desc: Use image node_id 12 for calling the StatelessRulesTests obj's underlying member method code with example usage: obj.test_NDaysBeforeLastTradingDayOfMonth() without return types