Question: when did the afl merge with the nfl
[{'answer': 'before the 1970 season', 'provenance': [{'wikipedia_id': '453767', 'title': 'AFL–NFL merger', 'start_paragraph_id': 1, 'start_character': 591, 'end_paragraph_id': 1, 'end_character': 613, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '453767', 'title': 'AFL–NFL merger', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 653, 'bleu_score': 0.9496016038707511, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6713949937462577634}, 'section': 'Section::::Abstract.'}]}]