Question: who sings with michael buble in white christmas
[{'answer': 'Shania Twain', 'provenance': [{'wikipedia_id': '32715741', 'title': 'Christmas (Michael Bublé album)', 'start_paragraph_id': 2, 'start_character': 322, 'end_paragraph_id': 2, 'end_character': 334, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '32715741', 'title': 'Christmas (Michael Bublé album)', 'start_paragraph_id': 4, 'start_character': 0, 'end_paragraph_id': 4, 'end_character': 913, 'bleu_score': 0.9320959495325901, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7906961214210859754}, 'section': 'Section::::Background.\n'}]}]