code: def test_dti_tz_localize_nonexistent_shift(
      self, start_ts, tz, end_ts, shift, tz_type, unit
  ):
      # GH#8917
      tz = tz_type + tz
      if isinstance(shift, str):
          shift = "shift_" + shift
      dti = DatetimeIndex([Timestamp(start_ts)]).as_unit(unit)
      result = dti.tz_localize(tz, nonexistent=shift)
      expected = (
          DatetimeIndex([Timestamp(end_ts)])
          .tz_localize(tz)
          .as_unit(unit)
      )
      tm.assert_index_equal(result, expected)
  
imports: from datetime import datetime, timedelta
  import dateutil.tz
  from dateutil.tz import gettz
  import numpy
  import pytest
  import pytz
  from pandas import DatetimeIndex, Timestamp, bdate_range, date_range, offsets, to_datetime
  import pandas._testing
label_desc: Use image node_id 18 for calling the TestTZLocalize obj's underlying member method code with example usage: obj.test_dti_tz_localize_nonexistent_shift(start_ts, tz, end_ts, shift, tz_type, unit) without return types