code: def test_constructor_iso(self):
      # GH #21877
      expected = timedelta_range("1s", periods=9, freq="s")
      durations = [f"P0DT0H0M{i}S" for i in range(1, 10)]
      result = to_timedelta(durations)
      tm.assert_index_equal(result, expected)
  
imports: from datetime import timedelta
  import numpy
  import pytest
  import pandas
  from pandas import Timedelta, TimedeltaIndex, timedelta_range, to_timedelta
  import pandas._testing
  from pandas.core.arrays.timedeltas import TimedeltaArray
label_desc: Use image node_id 12 for calling the TestTimedeltaIndex obj's underlying member method code with example usage: obj.test_constructor_iso() without return types