Question: when did the oilers last win the stanley cup
[{'answer': '1989 -- 90'}, {'provenance': [{'wikipedia_id': '73129', 'title': 'Edmonton Oilers', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 569, 'bleu_score': 0.838744049947817, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15431541254147624972}, 'section': 'Section::::Abstract.'}]}]