Question: when does lexie grey leave grey's anatomy
[{'answer': 'the eighth - season finale', 'provenance': [{'wikipedia_id': '11340577', 'title': 'Lexie Grey', 'start_paragraph_id': 27, 'start_character': 202, 'end_paragraph_id': 27, 'end_character': 227, 'bleu_score': 1.0, 'section': 'Section::::Development.:Casting and creation.\n'}]}, {'provenance': [{'wikipedia_id': '11340577', 'title': 'Lexie Grey', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 656, 'bleu_score': 0.632046398283407, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12310344764704293795}, 'section': 'Section::::Abstract.'}]}]