Question: when did the song lean on me come out
[{'answer': 'April 1972', 'provenance': [{'wikipedia_id': '4210382', 'title': 'Lean on Me (song)', 'start_paragraph_id': 1, 'start_character': 107, 'end_paragraph_id': 1, 'end_character': 117, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '4210382', 'title': 'Lean on Me (song)', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 583, 'bleu_score': 0.9041176456417931, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8936903215622703071}, 'section': 'Section::::Abstract.'}]}]