Question: what kind of roof does the at&t stadium have
[{'answer': 'retractable', 'provenance': [{'wikipedia_id': '6549393', 'title': 'AT&T Stadium', 'start_paragraph_id': 1, 'start_character': 45, 'end_paragraph_id': 1, 'end_character': 56, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '6549393', 'title': 'AT&T Stadium', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 636, 'bleu_score': 0.914276245058609, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4949036350012587792}, 'section': 'Section::::Abstract.'}]}]