Question: when did the british royal house change its name from saxe-coburg and gotha to windsor
[{'answer': '1917', 'provenance': [{'wikipedia_id': '172905', 'title': 'House of Windsor', 'start_paragraph_id': 2, 'start_character': 100, 'end_paragraph_id': 2, 'end_character': 104, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '172905', 'title': 'House of Windsor', 'start_paragraph_id': 2, 'start_character': 128, 'end_paragraph_id': 2, 'end_character': 677, 'bleu_score': 0.70113210053057, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5180366540223840838}, 'section': 'Section::::Abstract.'}]}]