Question: what is the area code for omaha nebraska
[{'answer': '402 ,', 'provenance': [{'wikipedia_id': '2467442', 'title': 'Area codes 402 and 531', 'start_paragraph_id': 4, 'start_character': 446, 'end_paragraph_id': 4, 'end_character': 456, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'provenance': [{'wikipedia_id': '2467442', 'title': 'Area codes 402 and 531', 'start_paragraph_id': 4, 'start_character': 0, 'end_paragraph_id': 4, 'end_character': 531, 'bleu_score': 0.950027409461844, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 205346141562106818}, 'section': 'Section::::History.\n'}]}]