Question: what is the latest season of american ninja warrior
[{'answer': 'eighth', 'provenance': [{'wikipedia_id': '47885045', 'title': 'American Ninja Warrior (season 8)', 'start_paragraph_id': 1, 'start_character': 4, 'end_paragraph_id': 1, 'end_character': 10, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '47885045', 'title': 'American Ninja Warrior (season 8)', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 483, 'bleu_score': 0.9738505480425671, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 140360422496099047}, 'section': 'Section::::Abstract.'}]}]