code: def test_sessions_in_range(self):
      # pick two sessions
      session_count = len(self.calendar.schedule.index)
  
      first_idx = int(session_count / 3)
      second_idx = 2 * first_idx
  
      first_session_label = self.calendar.schedule.index[first_idx]
      second_session_label = self.calendar.schedule.index[second_idx]
  
      answer_key = self.calendar.schedule.index[
          first_idx : second_idx + 1
      ]
  
      np.testing.assert_array_equal(
          answer_key,
          self.calendar.sessions_in_range(
              first_session_label, second_session_label
          ),
      )
  
imports: from datetime import time
  from os.path import abspath, dirname, join
  from unittest import TestCase
  import numpy
  import pandas
  from nose_parameterized import parameterized
  from pandas import read_csv
  from pandas.tslib import Timedelta
  from pandas.util.testing import assert_index_equal
  from pytz import timezone
  from toolz import concat
  from catalyst.errors import CalendarNameCollision, InvalidCalendarName
  from catalyst.testing.predicates import assert_equal
  from catalyst.utils.calendars import deregister_calendar, get_calendar, register_calendar
  from catalyst.utils.calendars.calendar_utils import _default_calendar_aliases, _default_calendar_factories, register_calendar_type
  from catalyst.utils.calendars.trading_calendar import days_at_time, TradingCalendar
label_desc: Use image node_id 14 for calling the ExchangeCalendarTestBase obj's underlying member method code with example usage: obj.test_sessions_in_range() without return types