Question: when was the last time the astro won the world series
[{'answer': '2017 World Series', 'provenance': [{'wikipedia_id': '13894', 'title': 'Houston Astros', 'start_paragraph_id': 3, 'start_character': 503, 'end_paragraph_id': 3, 'end_character': 520, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '13894', 'title': 'Houston Astros', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 608, 'bleu_score': 0.745880922522275, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14394871830085128721}, 'section': 'Section::::Abstract.'}]}]