code: def test_misc_coverage(self):
      rng = date_range("1/1/2000", periods=5)
      result = rng.groupby(rng.day)
      assert isinstance(next(iter(result.values()))[0], Timestamp)
  
imports: import datetime
  from datetime import date
  import re
  import numpy
  import pytest
  from pandas.compat.numpy import np_long
  import pandas
  from pandas import DataFrame, DatetimeIndex, Index, Timestamp, date_range, offsets
  import pandas._testing
label_desc: Use image node_id 6 for calling the TestDatetimeIndex obj's underlying member method code with example usage: obj.test_misc_coverage() without return types