Question: when did canada become independent from the british empire
[{'answer': '1931', 'provenance': [{'wikipedia_id': '52477', 'title': 'History of Canada', 'start_paragraph_id': 3, 'start_character': 207, 'end_paragraph_id': 3, 'end_character': 211, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '52477', 'title': 'History of Canada', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 579, 'bleu_score': 0.9505764710553931, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12140608585951377872}, 'section': 'Section::::Abstract.'}]}]