Question: who plays izzie stevens on grey's anatomy
[{'answer': 'Katherine Heigl', 'provenance': [{'wikipedia_id': '7687022', 'title': 'Izzie Stevens', 'start_paragraph_id': 1, 'start_character': 288, 'end_paragraph_id': 1, 'end_character': 303, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '7687022', 'title': 'Izzie Stevens', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 637, 'bleu_score': 0.9571530040022431, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17348504713802861227}, 'section': 'Section::::Abstract.'}]}]