[python][sequencer][tests] test case , removed old comments

Author: Patryk Dudziński

python/pyarrow/tests/test_table.py

@@ -2978,14 +2978,10 @@ def sorted_by_keys(d):
 
 @pytest.mark.acero
 def test_table_group_by_first():
-    # "first" is an ordered aggregation -> requires to specify use_threads=False
     table1 = pa.table({'a': [1, 2, 3, 4], 'b': ['a', 'b'] * 2})
     table2 = pa.table({'a': [1, 2, 3, 4], 'b': ['b', 'a'] * 2})
     table = pa.concat_tables([table1, table2])
 
-    # with pytest.raises(NotImplementedError):
-    #     table.group_by("b").aggregate([("a", "first")])
-
     result = table.group_by("b", use_threads=True).aggregate([("a", "first")])
     expected = pa.table({"b": ["a", "b"], "a_first": [1, 2]})
     assert result.equals(expected)