code: def test_astype_timedelta64_with_np_nan(self):
      # GH45798
      result = Series([Timedelta(1), np.nan], dtype="timedelta64[ns]")
      expected = Series([Timedelta(1), NaT], dtype="timedelta64[ns]")
      tm.assert_series_equal(result, expected)
  
imports: from datetime import datetime, timedelta
  from importlib import reload
  import string
  import sys
  import numpy
  import pytest
  from pandas._libs.tslibs import iNaT
  import pandas.util._test_decorators
  from pandas import NA, Categorical, CategoricalDtype, DatetimeTZDtype, Index, Interval, NaT, Series, Timedelta, Timestamp, cut, date_range, to_datetime
  import pandas._testing
label_desc: Use image node_id 9 for calling the TestAstypeCategorical obj's underlying member method code with example usage: obj.test_astype_timedelta64_with_np_nan() without return types