Question: when did george lucas come up with the idea of star wars
[{'answer': '1973', 'provenance': [{'wikipedia_id': '26678', 'title': 'Star Wars', 'start_paragraph_id': 15, 'start_character': 194, 'end_paragraph_id': 15, 'end_character': 198, 'bleu_score': 1.0, 'section': 'Section::::Film.:Skywalker saga.:Original trilogy.\n'}]}]