Question: who did pittsburgh play for the stanley cup 2017
[{'answer': 'Nashville Predators', 'provenance': [{'wikipedia_id': '50876707', 'title': '2017 Stanley Cup Finals', 'start_paragraph_id': 1, 'start_character': 292, 'end_paragraph_id': 1, 'end_character': 311, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '50876707', 'title': '2017 Stanley Cup Finals', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 473, 'bleu_score': 0.902369289936745, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15574717966332119418}, 'section': 'Section::::Abstract.'}]}]