Question: where did the bantu of east and southern africa migrate from
[{'answer': 'West Africa', 'provenance': [{'wikipedia_id': '430134', 'title': 'Bantu expansion', 'start_paragraph_id': 1, 'start_character': 148, 'end_paragraph_id': 1, 'end_character': 159, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]