code: def test_at_time_datetimeindex(self):
      index = date_range("2012-01-01", "2012-01-05", freq="30min")
      df = DataFrame(
          np.random.default_rng(2).standard_normal((len(index), 5)),
          index=index,
      )
      akey = time(12, 0, 0)
      ainds = [24, 72, 120, 168]
  
      result = df.at_time(akey)
      expected = df.loc[akey]
      expected2 = df.iloc[ainds]
      tm.assert_frame_equal(result, expected)
      tm.assert_frame_equal(result, expected2)
      assert len(result) == 4
  
file_path: pandas/pandas/tests/frame/methods/test_at_time.py
imports: from datetime import time
  import numpy
  import pytest
  import pytz
  from pandas._libs.tslibs import timezones
  from pandas import DataFrame, date_range
  import pandas._testing
label_desc: Use image node_id 9 for calling the TestAtTime obj's underlying member method code with example usage: obj.test_at_time_datetimeindex() without return types