code: def test_dti_nanosecond(self):
      dti = DatetimeIndex(np.arange(10))
      expected = Index(np.arange(10, dtype=np.int32))
  
      tm.assert_index_equal(dti.nanosecond, expected)
  
imports: import calendar
  from datetime import date, datetime, time
  import locale
  import unicodedata
  import numpy
  import pytest
  from pandas._libs.tslibs import timezones
  from pandas import DatetimeIndex, Index, NaT, Timestamp, date_range, offsets
  import pandas._testing
  from pandas.core.arrays import DatetimeArray
label_desc: Use image node_id 8 for calling the TestDatetimeIndexOps obj's underlying member method code with example usage: obj.test_dti_nanosecond() without return types