Question: chilean footballer who joined manchester united from arsenal in 2018
[{'answer': 'Alexis Sánchez', 'provenance': [{'wikipedia_id': '5901324', 'title': 'Alexis Sánchez', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 14, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]