Question: what movie did natalie portman win an oscar for
[{'answer': 'Black Swan', 'provenance': [{'wikipedia_id': '33509371', 'title': 'List of awards and nominations received by Natalie Portman', 'start_paragraph_id': 1, 'start_character': 163, 'end_paragraph_id': 1, 'end_character': 173, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '33509371', 'title': 'List of awards and nominations received by Natalie Portman', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 180, 'bleu_score': 0.9271474438253491, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8747225799680254450}, 'section': 'Section::::Abstract.'}]}]