Question: who does seth macfarlane voice in american dad
[{'answer': 'Stan Smith', 'provenance': [{'wikipedia_id': '908663', 'title': 'American Dad!', 'start_paragraph_id': 13, 'start_character': 0, 'end_paragraph_id': 13, 'end_character': 10, 'bleu_score': 1.0, 'section': 'Section::::Cast and characters.:Main characters.\n'}]}, {'answer': 'Roger', 'provenance': [{'wikipedia_id': '908663', 'title': 'American Dad!', 'start_paragraph_id': 7, 'start_character': 548, 'end_paragraph_id': 7, 'end_character': 553, 'bleu_score': 1.0, 'section': 'Section::::Premise.\n'}]}, {'provenance': [{'wikipedia_id': '908663', 'title': 'American Dad!', 'start_paragraph_id': 14, 'start_character': 0, 'end_paragraph_id': 14, 'end_character': 79, 'bleu_score': 0.8070557274927981, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9397037003444557395}, 'section': 'Section::::Cast and characters.:Main characters.\n'}]}]