code: def test_astype_object(self):
      rng = date_range("1/1/2000", periods=20)
  
      casted = rng.astype("O")
      exp_values = list(rng)
  
      tm.assert_index_equal(casted, Index(exp_values, dtype=np.object_))
      assert casted.tolist() == exp_values
  
imports: from datetime import datetime
  import dateutil
  import numpy
  import pytest
  import pytz
  import pandas
  from pandas import DatetimeIndex, Index, NaT, PeriodIndex, Timestamp, date_range
  import pandas._testing
label_desc: Use image node_id 14 for calling the TestDatetimeIndex obj's underlying member method code with example usage: obj.test_astype_object() without return types