Question: who sold the louisiana purchase to the us
[{'answer': 'Napoleon', 'provenance': [{'wikipedia_id': '17628', 'title': 'Louisiana Purchase', 'start_paragraph_id': 1, 'start_character': 306, 'end_paragraph_id': 1, 'end_character': 314, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]