Question: who starred in o brother where art thou
[{'answer': 'George Clooney', 'provenance': [{'wikipedia_id': '22216', 'title': 'O Brother, Where Art Thou?', 'start_paragraph_id': 1, 'start_character': 124, 'end_paragraph_id': 1, 'end_character': 138, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'John Turturro', 'provenance': [{'wikipedia_id': '22216', 'title': 'O Brother, Where Art Thou?', 'start_paragraph_id': 1, 'start_character': 140, 'end_paragraph_id': 1, 'end_character': 153, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'Tim Blake Nelson', 'provenance': [{'wikipedia_id': '22216', 'title': 'O Brother, Where Art Thou?', 'start_paragraph_id': 1, 'start_character': 159, 'end_paragraph_id': 1, 'end_character': 175, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '22216', 'title': 'O Brother, Where Art Thou?', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 249, 'bleu_score': 0.9517713210466091, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10689628101546213094}, 'section': 'Section::::Abstract.'}]}]