Question: what is the 2 letter postal code for nebraska
[{'answer': 'NE', 'provenance': [{'wikipedia_id': '399492', 'title': 'List of U.S. state abbreviations', 'start_paragraph_id': 8, 'start_character': 137, 'end_paragraph_id': 8, 'end_character': 139, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}]