code: def test_days_at_time(
      self, day, day_offset, time_offset, tz, expected
  ):
      days = pd.DatetimeIndex([pd.Timestamp(day, tz=tz)])
      result = days_at_time(days, time_offset, tz, day_offset)[0]
      expected = pd.Timestamp(expected, tz=tz).tz_convert("UTC")
      self.assertEqual(result, expected)
  
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 1 for calling the DaysAtTimeTestCase obj's underlying member method code with example usage: obj.test_days_at_time(day, day_offset, time_offset, tz, expected) without return types