Question: who plays the acting president on madam secretary
[{'answer': 'Keith Carradine', 'provenance': [{'wikipedia_id': '42740374', 'title': 'Madam Secretary (TV series)', 'start_paragraph_id': 17, 'start_character': 12, 'end_paragraph_id': 17, 'end_character': 27, 'bleu_score': 1.0, 'section': 'Section::::Cast and characters.:Main.\n'}]}, {'provenance': [{'wikipedia_id': '42740374', 'title': 'Madam Secretary (TV series)', 'start_paragraph_id': 17, 'start_character': 0, 'end_paragraph_id': 17, 'end_character': 669, 'bleu_score': 0.773942493022415, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 13096074232095300951}, 'section': 'Section::::Cast and characters.:Main.\n'}]}]