Question: who does the voice of princess fiona in shrek
[{'answer': 'Cameron Diaz', 'provenance': [{'wikipedia_id': '18717177', 'title': 'Shrek', 'start_paragraph_id': 1, 'start_character': 247, 'end_paragraph_id': 1, 'end_character': 259, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]