Question: who sings the song at the end of the huntsman winter's war
[{'answer': 'Halsey', 'provenance': [{'wikipedia_id': '50096972', 'title': 'Castle (Halsey song)', 'start_paragraph_id': 0, 'start_character': 8, 'end_paragraph_id': 0, 'end_character': 14, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '50096972', 'title': 'Castle (Halsey song)', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 591, 'bleu_score': 0.8746510800197551, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 18008639518487893533}, 'section': 'Section::::Abstract.'}]}]