Question: who played the warden in cool hand luke
[{'answer': 'Strother Martin', 'provenance': [{'wikipedia_id': '161897', 'title': 'Cool Hand Luke', 'start_paragraph_id': 4, 'start_character': 801, 'end_paragraph_id': 4, 'end_character': 816, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]