Question: when is the last time the pirates won the world series
[{'answer': '1979', 'provenance': [{'wikipedia_id': '24270', 'title': 'Pittsburgh Pirates', 'start_paragraph_id': 2, 'start_character': 611, 'end_paragraph_id': 2, 'end_character': 615, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '24270', 'title': 'Pittsburgh Pirates', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 692, 'bleu_score': 0.9843125095516201, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8209020225994888384}, 'section': 'Section::::Abstract.'}]}]