Question: who plays dr doofenshmirtz on phineas and ferb
[{'answer': 'Dan Povenmire', 'provenance': [{'wikipedia_id': '25246506', 'title': 'Dr. Heinz Doofenshmirtz', 'start_paragraph_id': 1, 'start_character': 155, 'end_paragraph_id': 1, 'end_character': 168, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]