Question: when did the metropolitan police force become a service
[{'answer': '29 September 1829', 'provenance': [{'wikipedia_id': '22423554', 'title': 'History of the Metropolitan Police Service', 'start_paragraph_id': 17, 'start_character': 51, 'end_paragraph_id': 17, 'end_character': 68, 'bleu_score': 1.0, 'section': 'Section::::19th century.\n'}]}, {'provenance': [{'wikipedia_id': '22423554', 'title': 'History of the Metropolitan Police Service', 'start_paragraph_id': 17, 'start_character': 0, 'end_paragraph_id': 17, 'end_character': 1011, 'bleu_score': 0.9873810715615521, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6819617693735288583}, 'section': 'Section::::19th century.\n'}]}]