code: def test_at_series_raises_key_error(self, indexer_al):
      # GH#31724 .at should match .loc
  
      ser = Series([1, 2, 3], index=[3, 2, 1])
      result = indexer_al(ser)[1]
      assert result == 3
  
      with pytest.raises(KeyError, match="a"):
          indexer_al(ser)["a"]
  
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 1 for calling the TestAtErrors obj's underlying member method code with example usage: obj.test_at_series_raises_key_error(indexer_al) without return types