code: def assert_index_parameters(self, index):
      assert index.freq == "40960ns"
      assert index.inferred_freq == "40960ns"
  
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 8 for calling the TestDatetimeIndex obj's underlying member method code with example usage: obj.assert_index_parameters(index) without return types