Question: who sings dream weaver on leon's commercial
[{'answer': 'Kevin Quain', 'provenance': [{'wikipedia_id': '2442717', 'title': 'Dream Weaver', 'start_paragraph_id': 38, 'start_character': 39, 'end_paragraph_id': 38, 'end_character': 50, 'bleu_score': 1.0, 'section': 'Section::::In other media.:Use by other musical artists.\n'}]}]