Question: what year did the vikings invade paris france
[{'answer': '845', 'provenance': [{'wikipedia_id': '34297243', 'title': 'Siege of Paris (845)', 'start_paragraph_id': 0, 'start_character': 16, 'end_paragraph_id': 0, 'end_character': 19, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]