Question: what is a period of 3 years called
[{'answer': 'triennium', 'provenance': [{'wikipedia_id': '695530', 'title': 'Decade', 'start_paragraph_id': 1, 'start_character': 191, 'end_paragraph_id': 1, 'end_character': 200, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '695530', 'title': 'Decade', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 297, 'bleu_score': 0.792942647668316, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6136013356525529565}, 'section': 'Section::::Abstract.'}]}]