Question: who wrote the clean air act of 1970
[{'answer': 'Edmund Muskie', 'provenance': [{'wikipedia_id': '19060778', 'title': 'Clean Air Act (United States)', 'start_paragraph_id': 70, 'start_character': 92, 'end_paragraph_id': 70, 'end_character': 105, 'bleu_score': 1.0, 'section': 'Section::::History.:Legislation.\n'}]}, {'provenance': [{'wikipedia_id': '19060778', 'title': 'Clean Air Act (United States)', 'start_paragraph_id': 70, 'start_character': 0, 'end_paragraph_id': 70, 'end_character': 133, 'bleu_score': 0.9146912192286941, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4605764655775083518}, 'section': 'Section::::History.:Legislation.\n'}]}]