code: def test_setitem_invalidates_datetime_index_freq(self):
      # GH#24096 altering a datetime64tz column inplace invalidates the
      #  `freq` attribute on the underlying DatetimeIndex
  
      dti = date_range("20130101", periods=3, tz="US/Eastern")
      ts = dti[1]
  
      df = DataFrame({"B": dti})
      assert df["B"]._values.freq is None
  
      df.iloc[1, 0] = pd.NaT
      assert df["B"]._values.freq is None
  
      # check that the DatetimeIndex was not altered in place
      assert dti.freq == "D"
      assert dti[1] == ts
  
imports: from datetime import datetime, timedelta
  import itertools
  import numpy
  import pytest
  from pandas.errors import PerformanceWarning
  import pandas
  from pandas import Categorical, DataFrame, Series, Timestamp, date_range, option_context
  import pandas._testing
  from pandas.core.internals.blocks import NumpyBlock
label_desc: Use image node_id 1 for calling the TestDataFrameBlockInternals obj's underlying member method code with example usage: obj.test_setitem_invalidates_datetime_index_freq() without return types