Question: who sings the song mama don't let your babies grow up to be cowboys
[{'answer': 'Ed Bruce', 'provenance': [{'wikipedia_id': '6773215', 'title': "Mammas Don't Let Your Babies Grow Up to Be Cowboys", 'start_paragraph_id': 1, 'start_character': 95, 'end_paragraph_id': 1, 'end_character': 103, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '6773215', 'title': "Mammas Don't Let Your Babies Grow Up to Be Cowboys", 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 554, 'bleu_score': 0.85606064569643, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17537319685533376858}, 'section': 'Section::::Abstract.'}]}]