Question: when did oasis of the seas first sail
[{'answer': '5 December 2009', 'provenance': [{'wikipedia_id': '17602306', 'title': 'Oasis of the Seas', 'start_paragraph_id': 8, 'start_character': 397, 'end_paragraph_id': 8, 'end_character': 412, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}]