Question: when was saturn last visited by a spacecraft
[{'answer': '2017', 'provenance': [{'wikipedia_id': '10844329', 'title': 'Exploration of Saturn', 'start_paragraph_id': 1, 'start_character': 245, 'end_paragraph_id': 1, 'end_character': 249, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '10844329', 'title': 'Exploration of Saturn', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 249, 'bleu_score': 0.9493253852526031, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14603185597411978094}, 'section': 'Section::::Abstract.'}]}]