Question: when did robert louis stevenson wrote his first book
[{'answer': '1883', 'provenance': [{'wikipedia_id': '26444', 'title': 'Robert Louis Stevenson', 'start_paragraph_id': 76, 'start_character': 31, 'end_paragraph_id': 76, 'end_character': 35, 'bleu_score': 1.0, 'section': 'Section::::Bibliography.:Novels.\n'}]}]