code: def test_insert(self):
      idx = TimedeltaIndex(["4day", "1day", "2day"], name="idx")
  
      result = idx.insert(2, timedelta(days=5))
      exp = TimedeltaIndex(["4day", "1day", "5day", "2day"], name="idx")
      tm.assert_index_equal(result, exp)
  
      # insertion of non-datetime should coerce to object index
      result = idx.insert(1, "inserted")
      expected = Index(
          [
              Timedelta("4day"),
              "inserted",
              Timedelta("1day"),
              Timedelta("2day"),
          ],
          name="idx",
      )
      assert not isinstance(result, TimedeltaIndex)
      tm.assert_index_equal(result, expected)
      assert result.name == expected.name
  
      idx = timedelta_range(
          "1day 00:00:01", periods=3, freq="s", name="idx"
      )
  
      # preserve freq
      expected_0 = TimedeltaIndex(
          ["1day", "1day 00:00:01", "1day 00:00:02", "1day 00:00:03"],
          name="idx",
          freq="s",
      )
      expected_3 = TimedeltaIndex(
          [
              "1day 00:00:01",
              "1day 00:00:02",
              "1day 00:00:03",
              "1day 00:00:04",
          ],
          name="idx",
          freq="s",
      )
  
      # reset freq to None
      expected_1_nofreq = TimedeltaIndex(
          [
              "1day 00:00:01",
              "1day 00:00:01",
              "1day 00:00:02",
              "1day 00:00:03",
          ],
          name="idx",
          freq=None,
      )
      expected_3_nofreq = TimedeltaIndex(
          [
              "1day 00:00:01",
              "1day 00:00:02",
              "1day 00:00:03",
              "1day 00:00:05",
          ],
          name="idx",
          freq=None,
      )
  
      cases = [
          (0, Timedelta("1day"), expected_0),
          (-3, Timedelta("1day"), expected_0),
          (3, Timedelta("1day 00:00:04"), expected_3),
          (1, Timedelta("1day 00:00:01"), expected_1_nofreq),
          (3, Timedelta("1day 00:00:05"), expected_3_nofreq),
      ]
  
      for n, d, expected in cases:
          result = idx.insert(n, d)
          tm.assert_index_equal(result, expected)
          assert result.name == expected.name
          assert result.freq == expected.freq
  
file_path: pandas/pandas/tests/indexes/timedeltas/methods/test_insert.py
imports: from datetime import timedelta
  import numpy
  import pytest
  from pandas._libs import lib
  import pandas
  from pandas import Index, Timedelta, TimedeltaIndex, timedelta_range
  import pandas._testing
label_desc: Use image node_id 1 for calling the TestTimedeltaIndexInsert obj's underlying member method code with example usage: obj.test_insert() without return types