Question: who was in power in russia during ww2
[{'answer': 'Joseph Stalin'}, {'provenance': [{'wikipedia_id': '21619085', 'title': 'Soviet Union in World War II', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 683, 'bleu_score': 0.7456815143574831, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3547294529094666917}, 'section': 'Section::::Abstract.'}]}]