code: def test_at_categorical_integers(self):
      # CategoricalIndex with integer categories that don't happen to match
      #  the Categorical's codes
      ci = CategoricalIndex([3, 4])
  
      arr = np.arange(4).reshape(2, 2)
      frame = DataFrame(arr, index=ci)
  
      for df in [frame, frame.T]:
          for key in [0, 1]:
              with pytest.raises(KeyError, match=str(key)):
                  df.at[key, key]
  
imports: from datetime import datetime, timezone
  import numpy
  import pytest
  from pandas.errors import InvalidIndexError
  from pandas import CategoricalDtype, CategoricalIndex, DataFrame, DatetimeIndex, Index, MultiIndex, Series, Timestamp
  import pandas._testing
label_desc: Use image node_id 7 for calling the TestAtErrors obj's underlying member method code with example usage: obj.test_at_categorical_integers() without return types