Question: where did the vikings play before the metrodome
[{'answer': 'Metropolitan Stadium', 'provenance': [{'wikipedia_id': '20134', 'title': 'Minnesota Vikings', 'start_paragraph_id': 6, 'start_character': 62, 'end_paragraph_id': 6, 'end_character': 82, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}]