Question: who sang the songs in mamma mia movie
[{'answer': "film 's cast", 'provenance': [{'wikipedia_id': '18606479', 'title': 'Mamma Mia! The Movie Soundtrack', 'start_paragraph_id': 1, 'start_character': 291, 'end_paragraph_id': 1, 'end_character': 312, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '18606479', 'title': 'Mamma Mia! The Movie Soundtrack', 'start_paragraph_id': 1, 'start_character': 77, 'end_paragraph_id': 1, 'end_character': 845, 'bleu_score': 0.8154443527656551, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15452382309140049769}, 'section': 'Section::::Abstract.'}]}]