Question: what is the airport code for louisville kentucky
[{'answer': 'SDF', 'provenance': [{'wikipedia_id': '264229', 'title': 'Louisville International Airport', 'start_paragraph_id': 1, 'start_character': 200, 'end_paragraph_id': 1, 'end_character': 203, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '264229', 'title': 'Louisville International Airport', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 402, 'bleu_score': 0.523591205524321, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11072468250488525266}, 'section': 'Section::::Abstract.'}]}]