Question: who wrote song all i want for christmas is you
[{'answer': 'Mariah Carey', 'provenance': [{'wikipedia_id': '1822980', 'title': 'All I Want for Christmas Is You', 'start_paragraph_id': 1, 'start_character': 98, 'end_paragraph_id': 1, 'end_character': 110, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'Walter Afanasieff', 'provenance': [{'wikipedia_id': '1822980', 'title': 'All I Want for Christmas Is You', 'start_paragraph_id': 1, 'start_character': 154, 'end_paragraph_id': 1, 'end_character': 171, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]