Question: who plays the old man in mary poppins
[{'answer': 'Dick Van Dyke', 'provenance': [{'wikipedia_id': '77856', 'title': 'Mary Poppins (film)', 'start_paragraph_id': 1, 'start_character': 504, 'end_paragraph_id': 1, 'end_character': 517, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '77856', 'title': 'Mary Poppins (film)', 'start_paragraph_id': 15, 'start_character': 0, 'end_paragraph_id': 15, 'end_character': 407, 'bleu_score': 0.5651703556573691, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8438783713952467947}, 'section': 'Section::::Cast.\n'}]}]