Question: what is the most established and iconic instrumental ensemble in western culture
[{'answer': 'bluegrass', 'provenance': [{'wikipedia_id': '60590', 'title': 'Bluegrass music', 'start_paragraph_id': 2, 'start_character': 213, 'end_paragraph_id': 2, 'end_character': 222, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '60590', 'title': 'Bluegrass music', 'start_paragraph_id': 17, 'start_character': 0, 'end_paragraph_id': 17, 'end_character': 909, 'bleu_score': 0.9687635332632951, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11630130298456810679}, 'section': 'Section::::History.:Creation.\n'}]}]