Question: who sang just a song before i go
[{'answer': 'Crosby , Stills and Nash', 'provenance': [{'wikipedia_id': '6856602', 'title': 'Just a Song Before I Go', 'start_paragraph_id': 4, 'start_character': 0, 'end_paragraph_id': 4, 'end_character': 32, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '6856602', 'title': 'Just a Song Before I Go', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 349, 'bleu_score': 0.8228971210240431, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11379008676265105731}, 'section': 'Section::::Abstract.'}]}]