Question: when was the forst harry potter book published
[{'answer': '1997', 'provenance': [{'wikipedia_id': '2270723', 'title': 'Harry Potter and the Half-Blood Prince', 'start_paragraph_id': 18, 'start_character': 198, 'end_paragraph_id': 18, 'end_character': 202, 'bleu_score': 1.0, 'section': 'Section::::Development.:Franchise.\n'}]}, {'provenance': [{'wikipedia_id': '2270723', 'title': 'Harry Potter and the Half-Blood Prince', 'start_paragraph_id': 18, 'start_character': 0, 'end_paragraph_id': 18, 'end_character': 1236, 'bleu_score': 0.9764096275665931, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8875120225500129398}, 'section': 'Section::::Development.:Franchise.\n'}]}]