code: def test_at_series_raises_key_error2(self, indexer_al):
      # at should not fallback
      # GH#7814
      # GH#31724 .at should match .loc
      ser = Series([1, 2, 3], index=list("abc"))
      result = indexer_al(ser)["a"]
      assert result == 1
  
      with pytest.raises(KeyError, match="^0$"):
          indexer_al(ser)[0]
  
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 3 for calling the TestAtErrors obj's underlying member method code with example usage: obj.test_at_series_raises_key_error2(indexer_al) without return types