code: def test_fillna_pytimedelta(self):
      # GH#8209
      ser = Series([np.nan, Timedelta("1 days")], index=["A", "B"])
  
      result = ser.fillna(timedelta(1))
      expected = Series(Timedelta("1 days"), index=["A", "B"])
      tm.assert_series_equal(result, expected)
  
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 18 for calling the TestSeriesFillNA obj's underlying member method code with example usage: obj.test_fillna_pytimedelta() without return types