Question: when did latvia gain independence from the soviet union
[{'answer': '1920', 'provenance': [{'wikipedia_id': '17762', 'title': 'History of Latvia', 'start_paragraph_id': 4, 'start_character': 249, 'end_paragraph_id': 4, 'end_character': 253, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '17762', 'title': 'History of Latvia', 'start_paragraph_id': 4, 'start_character': 0, 'end_paragraph_id': 4, 'end_character': 688, 'bleu_score': 0.9656620171147301, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 83956965788306439}, 'section': 'Section::::Abstract.'}]}]