Question: who wrote the songs for peter paul and mary
[{'answer': 'Yarrow and Stookey', 'provenance': [{'wikipedia_id': '158205', 'title': 'Peter, Paul and Mary', 'start_paragraph_id': 1, 'start_character': 281, 'end_paragraph_id': 1, 'end_character': 299, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '158205', 'title': 'Peter, Paul and Mary', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 482, 'bleu_score': 0.860162552725062, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11883517966831416744}, 'section': 'Section::::Abstract.'}]}]