Question: which us professional sports franchise has the highest value
[{'answer': 'Dallas Cowboys', 'provenance': [{'wikipedia_id': '44968038', 'title': "Forbes' list of the most valuable sports teams", 'start_paragraph_id': 2, 'start_character': 13, 'end_paragraph_id': 2, 'end_character': 27, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]