Question: who sings the lead in dream on by aerosmith
[{'answer': 'Steven Tyler', 'provenance': [{'wikipedia_id': '2761666', 'title': 'Dream On (Aerosmith song)', 'start_paragraph_id': 1, 'start_character': 107, 'end_paragraph_id': 1, 'end_character': 119, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]