Question: what is the latest version of imac os
[{'answer': 'macOS High Sierra', 'provenance': [{'wikipedia_id': '20640', 'title': 'MacOS', 'start_paragraph_id': 22, 'start_character': 696, 'end_paragraph_id': 22, 'end_character': 713, 'bleu_score': 1.0, 'section': 'Section::::History.:Mac OS X.:Following releases.\n'}]}]