Question: who sang silver bells with blake shelton on the voice
[{'answer': 'Xenia', 'provenance': [{'wikipedia_id': '32167074', 'title': 'Xenia (singer)', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 5, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '32167074', 'title': 'Xenia (singer)', 'start_paragraph_id': 12, 'start_character': 0, 'end_paragraph_id': 12, 'end_character': 144, 'bleu_score': 0.9181891462193901, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14854266676813976127}, 'section': 'Section::::Life and career.:2011–present: "Sing You Home", collaboration with Blake Shelton, and "Artemisa".\n'}]}]