Question: when was the name madras changed to chennai
[{'answer': '17 July 1996', 'provenance': [{'wikipedia_id': '45139', 'title': 'Chennai', 'start_paragraph_id': 19, 'start_character': 507, 'end_paragraph_id': 19, 'end_character': 519, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'provenance': [{'wikipedia_id': '45139', 'title': 'Chennai', 'start_paragraph_id': 19, 'start_character': 0, 'end_paragraph_id': 19, 'end_character': 909, 'bleu_score': 0.9569209917145891, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 1649480982871949322}, 'section': 'Section::::History.\n'}]}]