Question: who plays the singer in the my little pony movie
[{'answer': 'Sia', 'provenance': [{'wikipedia_id': '51068079', 'title': 'My Little Pony: The Movie (2017 film)', 'start_paragraph_id': 1, 'start_character': 725, 'end_paragraph_id': 1, 'end_character': 728, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '51068079', 'title': 'My Little Pony: The Movie (2017 film)', 'start_paragraph_id': 21, 'start_character': 0, 'end_paragraph_id': 21, 'end_character': 136, 'bleu_score': 0.910879922930628, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4169396909457579137}, 'section': 'Section::::Cast.\n'}]}]