Question: when did the first episode of saved by the bell air
[{'answer': 'August 20 , 1989', 'provenance': [{'wikipedia_id': '93494', 'title': 'Saved by the Bell', 'start_paragraph_id': 23, 'start_character': 365, 'end_paragraph_id': 23, 'end_character': 381, 'bleu_score': 1.0, 'section': 'Section::::Production.:"Saved by the Bell".\n'}]}]