Question: who danced the lead role in appalachian spring
[{'answer': 'Martha Graham', 'provenance': [{'wikipedia_id': '1346977', 'title': 'Appalachian Spring', 'start_paragraph_id': 1, 'start_character': 279, 'end_paragraph_id': 1, 'end_character': 292, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1346977', 'title': 'Appalachian Spring', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 598, 'bleu_score': 0.9177120868939821, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 18429794722106914769}, 'section': 'Section::::Abstract.'}]}]