code: def test_dt_round_tz_nonexistent(self, method, ts_str, freq):
      # GH 23324 round near "spring forward" DST
      ser = Series([pd.Timestamp(ts_str, tz="America/Chicago")])
      result = getattr(ser.dt, method)(
          freq, nonexistent="shift_forward"
      )
      expected = Series(
          [pd.Timestamp("2018-03-11 03:00:00", tz="America/Chicago")]
      )
      tm.assert_series_equal(result, expected)
  
      result = getattr(ser.dt, method)(freq, nonexistent="NaT")
      expected = Series([pd.NaT]).dt.tz_localize(result.dt.tz)
      tm.assert_series_equal(result, expected)
  
      with pytest.raises(
          pytz.NonExistentTimeError, match="2018-03-11 02:00:00"
      ):
          getattr(ser.dt, method)(freq, nonexistent="raise")
  
imports: import calendar
  from datetime import date, datetime, time
  import locale
  import unicodedata
  import numpy
  import pytest
  import pytz
  from pandas._libs.tslibs.timezones import maybe_get_tz
  from pandas.errors import SettingWithCopyError
  from pandas.core.dtypes.common import is_integer_dtype, is_list_like
  import pandas
  from pandas import DataFrame, DatetimeIndex, Index, Period, PeriodIndex, Series, TimedeltaIndex, date_range, period_range, timedelta_range
  import pandas._testing
  from pandas.core.arrays import DatetimeArray, PeriodArray, TimedeltaArray
label_desc: Use image node_id 13 for calling the TestSeriesDatetimeValues obj's underlying member method code with example usage: obj.test_dt_round_tz_nonexistent(method, ts_str, freq) without return types