Question: who is the first chairman of the african union
[{'answer': 'Thabo Mbeki', 'provenance': [{'wikipedia_id': '30862870', 'title': 'Chairperson of the African Union', 'start_paragraph_id': 4, 'start_character': 33, 'end_paragraph_id': 4, 'end_character': 44, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}]