code: def test_fillna_dt64tz_with_method(self):
      # with timezone
      # GH#15855
      ser = Series([Timestamp("2012-11-11 00:00:00+01:00"), NaT])
      exp = Series(
          [
              Timestamp("2012-11-11 00:00:00+01:00"),
              Timestamp("2012-11-11 00:00:00+01:00"),
          ]
      )
      tm.assert_series_equal(ser.fillna(method="pad"), exp)
  
      ser = Series([NaT, Timestamp("2012-11-11 00:00:00+01:00")])
      exp = Series(
          [
              Timestamp("2012-11-11 00:00:00+01:00"),
              Timestamp("2012-11-11 00:00:00+01:00"),
          ]
      )
      tm.assert_series_equal(ser.fillna(method="bfill"), exp)
  
imports: from datetime import datetime, timedelta, timezone
  import numpy
  import pytest
  import pytz
  from pandas import Categorical, DataFrame, DatetimeIndex, NaT, Period, Series, Timedelta, Timestamp, date_range, isna, timedelta_range
  import pandas._testing
  from pandas.core.arrays import period_array
label_desc: Use image node_id 17 for calling the TestSeriesFillNA obj's underlying member method code with example usage: obj.test_fillna_dt64tz_with_method() without return types