Question: when was central air conditioning invented for homes
[{'answer': '1950s', 'provenance': [{'wikipedia_id': '7221088', 'title': 'Air conditioning', 'start_paragraph_id': 18, 'start_character': 891, 'end_paragraph_id': 18, 'end_character': 896, 'bleu_score': 1.0, 'section': 'Section::::History.:Electrical air conditioning.\n'}]}, {'provenance': [{'wikipedia_id': '7221088', 'title': 'Air conditioning', 'start_paragraph_id': 18, 'start_character': 0, 'end_paragraph_id': 18, 'end_character': 896, 'bleu_score': 0.9858648355536391, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10738116503888989681}, 'section': 'Section::::History.:Electrical air conditioning.\n'}]}]