code: def test_to_timedelta_null(self):
      result = to_timedelta(["", ""])
      assert isna(result).all()
  
imports: from datetime import time, timedelta
  import numpy
  import pytest
  from pandas.compat import IS64
  from pandas.errors import OutOfBoundsTimedelta
  import pandas
  from pandas import Series, TimedeltaIndex, isna, to_timedelta
  import pandas._testing
  from pandas.core.arrays import TimedeltaArray
label_desc: Use image node_id 3 for calling the TestTimedeltas obj's underlying member method code with example usage: obj.test_to_timedelta_null() without return types