Question: who does helena bonham carter play in merlin
[{'answer': 'Morgan le Fay', 'provenance': [{'wikipedia_id': '1323663', 'title': 'Merlin (miniseries)', 'start_paragraph_id': 9, 'start_character': 585, 'end_paragraph_id': 9, 'end_character': 598, 'bleu_score': 1.0, 'section': 'Section::::Plot.\n'}]}]