Question: who sang the original version of lean on me
[{'answer': 'Bill Withers', 'provenance': [{'wikipedia_id': '4210382', 'title': 'Lean on Me (song)', 'start_paragraph_id': 1, 'start_character': 74, 'end_paragraph_id': 1, 'end_character': 86, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]