Question: when did latvia become part of the soviet union
[{'answer': '5 August 1940', 'provenance': [{'wikipedia_id': '380350', 'title': 'Latvian Soviet Socialist Republic', 'start_paragraph_id': 3, 'start_character': 108, 'end_paragraph_id': 3, 'end_character': 121, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '380350', 'title': 'Latvian Soviet Socialist Republic', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 653, 'bleu_score': 0.9476834831213011, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17162254994647564899}, 'section': 'Section::::Abstract.'}]}]