Question: who did mos def play in cadillac records
[{'answer': 'Chuck Berry', 'provenance': [{'wikipedia_id': '16627853', 'title': 'Cadillac Records', 'start_paragraph_id': 2, 'start_character': 97, 'end_paragraph_id': 2, 'end_character': 108, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '16627853', 'title': 'Cadillac Records', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 311, 'bleu_score': 0.962600167205617, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3776717887908429593}, 'section': 'Section::::Abstract.'}]}]