Question: who sang west texas town of el paso
[{'answer': 'Marty Robbins', 'provenance': [{'wikipedia_id': '2256589', 'title': 'El Paso (song)', 'start_paragraph_id': 1, 'start_character': 77, 'end_paragraph_id': 1, 'end_character': 90, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '2256589', 'title': 'El Paso (song)', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 911, 'bleu_score': 0.9871375943883031, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 13826290537282393752}, 'section': 'Section::::Abstract.'}]}]