Question: what was the oldest form on government in greece
[{'answer': 'oligarchy', 'provenance': [{'wikipedia_id': '1827032', 'title': 'History of democracy', 'start_paragraph_id': 8, 'start_character': 542, 'end_paragraph_id': 8, 'end_character': 551, 'bleu_score': 1.0, 'section': 'Section::::Antiquity.:Historic origins.\n'}]}, {'provenance': [{'wikipedia_id': '1827032', 'title': 'History of democracy', 'start_paragraph_id': 20, 'start_character': 0, 'end_paragraph_id': 20, 'end_character': 721, 'bleu_score': 0.981898582188057, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15548717573254042690}, 'section': 'Section::::Antiquity.:Proto-democratic societies.:Sparta.\n'}]}]