Question: who was the first elected prime minister of britain
[{'answer': 'Sir Robert Walpole', 'provenance': [{'wikipedia_id': '2152548', 'title': 'List of Prime Ministers of the United Kingdom', 'start_paragraph_id': 1, 'start_character': 619, 'end_paragraph_id': 1, 'end_character': 637, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '2152548', 'title': 'List of Prime Ministers of the United Kingdom', 'start_paragraph_id': 1, 'start_character': 4, 'end_paragraph_id': 1, 'end_character': 928, 'bleu_score': 0.777763284704429, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15740323886659916247}, 'section': 'Section::::Abstract.'}]}]