Question: when did the nissan leaf first come out
[{'answer': 'in December 2010', 'provenance': [{'wikipedia_id': '23833126', 'title': 'Nissan Leaf', 'start_paragraph_id': 1, 'start_character': 131, 'end_paragraph_id': 1, 'end_character': 147, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]