Question: who plays sierra in the affair season 4
[{'answer': 'Emily Browning', 'provenance': [{'wikipedia_id': '43692038', 'title': 'The Affair (TV series)', 'start_paragraph_id': 36, 'start_character': 12, 'end_paragraph_id': 36, 'end_character': 26, 'bleu_score': 1.0, 'section': 'Section::::Cast.:Recurring cast.\n'}]}]