Question: what year did the movie grease take place
[{'answer': '1958', 'provenance': [{'wikipedia_id': '336846', 'title': 'Grease (film)', 'start_paragraph_id': 5, 'start_character': 17, 'end_paragraph_id': 5, 'end_character': 21, 'bleu_score': 1.0, 'section': 'Section::::Plot.\n'}]}]