Question: when was the last time the canadian anthem changed
[{'answer': 'January 31 , 2018', 'provenance': [{'wikipedia_id': '22504', 'title': 'O Canada', 'start_paragraph_id': 56, 'start_character': 537, 'end_paragraph_id': 56, 'end_character': 557, 'bleu_score': 1.0, 'section': 'Section::::History.:Inclusive language debates.\n'}]}, {'provenance': [{'wikipedia_id': '22504', 'title': 'O Canada', 'start_paragraph_id': 56, 'start_character': 0, 'end_paragraph_id': 56, 'end_character': 599, 'bleu_score': 0.8950582352609551, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14232905835587406097}, 'section': 'Section::::History.:Inclusive language debates.\n'}]}]