Question: when did the san diego chargers become the los angeles chargers
[{'answer': '2017', 'provenance': [{'wikipedia_id': '27170', 'title': 'Los Angeles Chargers', 'start_paragraph_id': 1, 'start_character': 677, 'end_paragraph_id': 1, 'end_character': 681, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '27170', 'title': 'Los Angeles Chargers', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 963, 'bleu_score': 0.9287576636349051, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16754167611420867493}, 'section': 'Section::::Abstract.'}]}]