Question: who does the voice over for optimus prime
[{'answer': 'Peter Claver Cullen', 'provenance': [{'wikipedia_id': '810826', 'title': 'Peter Cullen', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 19, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '810826', 'title': 'Peter Cullen', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 528, 'bleu_score': 0.8799747896071861, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7668860325395120582}, 'section': 'Section::::Abstract.'}]}]